This is a chronology of the events of the Back to the Future universe, including the animated series and the comics.
1st century A.D.
- Date unknown: Bifficus Antanneny is born.
- 36: Marty McFly arrives in ancient Rome under the alias "Marticus" and Bifficus Antanneny challenges Marticus to a chariot race. Bifficus must win the race in order to remain popular with the masses, in order that Caligula succeeds Tiberius Caesar as Emperor in 37 A.D., an event that Doc sees as the turning point in the decline of the Roman Empire. 
- Date unknown: Lord Biffingham of Tannenshire is born.
- Date unknown: Harold McFly is born.
- Date unknown: Jennivere McFly is born.
- 1367: The Brown family arrive in Medieval England because Doc thinks his family has become too reliant on technology. Clara is kidnapped by Lord Biffingham of Tannenshire. Doc, his sons Jules and Verne, and Harold McFly tried to save them and were to be beheaded, Clara and Jennivere saved Doc, Jules, Verne, and Harold, and Harold and Jennivere decided to immigrate to Ireland to raise "generations of McFlys" while the Brown family went back to Hill Valley.
- 1692: The Brown family arrives in Salem, Massachusetts, in August. After a month, Doc has developed the technology to send a letter to Marty, who arrives on September 23. 
- 1697: Marty and Verne visit a Spanish colony in the Caribbean, and Marty impersonates pirate Mac the Black. 
- Dates unknown: The earliest of Doc's emergency money is printed.
- Date unknown: Thaddeus Tannen forces Wendell Parker to sign a deed to the Parker Ranch, but buries the paper.
- Date unknown: Beauregard Tannen moves to Hill Valley after the Civil War and starts building a saloon
- Monday, July 17: Edna Strickland arrives in the past under the name "Mary Pickford" and tries to burn down Tannen's saloon, but ends up burning Hill Valley with it. However, Doc and Marty arrive to stop her abd get her back to 1931, there, Marty sees a portrait of his grandma Sylvia's ancestor, Delores.
- Seamus McFly, his wife Maggie McFly and his brother Martin emigrate from Ireland to the United States. They take a few years to get to California, shortly setting in Virginia City, Nevada along the way. Martin starts a bar fight there after someone calls him "yellow," and is stabbed to death as a result.
- Thursday, January 1
- Date unknown between January 1 and September 3: Blacksmith Emmett Brown is hired by Buford Tannen to shoe Buford's horse, but is not paid. After getting thrown off his horse and breaking a bottle of whiskey, Buford blames Doc for the accident and demands a total of eighty dollars from him; five dollars for the whiskey and seventy-five dollars for the horse, which was shot.
- April: William Sean McFly born, first son to Seamus and Maggie McFly and the first McFly born in America.
- Saturday, July 4: Doc passes out after drinking one shot of whiskey at the 4th of July celebrations.
- Saturday, August 29: There is a meeting of the townspeople over who will pick up the new schoolteacher on September 4. Doc volunteers.
- Tuesday, September 1: Doc buries the broken DeLorean time machine in the Delgado Mine. He writes a letter to be delivered personally by Western Union to Marty McFly on November 12, 1955 exactly at 9:45 p.m. to the exact stretch of road he was hovering above when he was struck by lightning.
- Wednesday, September 2:
- 8:00 a.m. Marty McFly arrives in 1885 to rescue Doc from impending doom. Native American Horseback-archers, who were on the run of the Federal Forces, shoot the fuel line in the time machine, leaving the DeLorean with no fuel at all. He later meets his ancestors Seamus, Maggie, and William McFly on the McFly farm and assumes the name "Clint Eastwood".
- Thursday, September 3: Marty runs into Buford "Mad Dog" Tannen, great grandfather of Biff Tannen, and upsets him, causing Tannen to nearly hang Marty. Doc saves Marty in time. Marty informs Doc of his impending death involving Clara Clayton and Buford Tannen. Aware that he will fall in love with Clara Clayton and worried about changing his future, Doc decides not to pick her up, as he has already volunteered to do five days ago.
- Friday, September 4:
- Saturday, September 5: The Hill Valley Festival. As part of Hill Valley’s anniversary festivities, the new courthouse clock is started at exactly 8:00 p.m. PST. Photographs with the clock are offered to townspeople wishing to pose with the new timepiece. The clock will remain in faithful service to Hill Valley for the next seven decades. Doc and Marty have a photograph taken, posing next to the new courthouse clock (this photo is given to Marty in 1985 by Doc at the spot where the DeLorean was destroyed by a locomotive near Eastwood Ravine). While Doc and Clara dance, Buford Tannen tries to shoot Doc, but Marty interferes and saves him.
- Sunday, September 6:
- 7:00 a.m. Marty wakes up. After being confronted by Doc about the dangers of fighting Buford, Marty checks his photograph from 1955, and gets a shock. The future of timeline 8 in which Doc is killed is replaced by one in which Marty, aka "Clint Eastwood", is likely to be killed. Doc and Marty prepare to go back to the future. Doc says goodbye to Clara and tells her the truth, but she doesn't believe him. Both are broken-hearted; she prepares to leave Hill Valley and he goes to a saloon. Buford and his gang rob the Pine City stage.
- Monday, September 7:
- 8:00 a.m.Marty has a showdown scheduled with Tannen; Marty and Doc are ready to escape through the back door when Tannen calls Marty "yellow". Marty still decides not to face Tannen, showing an incredible amount of growth from a mere day earlier, and is about to walk away when Tannen's gang gets a hold of Doc and threatens to shoot him.
- Marty then decides to face Tannen, and survives due to a trick learned from the Clint Eastwood movie A Fistful of Dollars (which was being watched by Biff in 1985A, in timeline 5). Again Marty checks the photo he has brought, and is relieved. The future of timeline 8 in which Marty is killed is replaced by one in which both Doc and Marty survive.
- Tannen and his gang are arrested for the robbery of the Pine City stage.
- Meanwhile, Clara Clayton, on a train bound for San Francisco, overhears a passenger talking about the heartsick Doc Brown; her belief restored, she stops the train and jumps off to find Doc. She discovers clues at the blacksmith shop and rides on horseback towards the spur line Doc and Marty are using. She must reach Doc before he vanishes forever.
- Doc and Marty are using a hijacked train's locomotive to push the DeLorean up to 88 mph toward Shonash Ravine so they may both go back to the future (1985). Marty succeeds in doing so, but Doc, who has gone to Clara's rescue on the accelerating locomotive, and Clara are forced to stay behind. Doc now has the hoverboard and one of the walkie talkies. Since "Clint" was observed stealing the engine, and is presumed to have gone down with it, he enters the town's folklore as the man who beat Mad Dog Tannen, and Shonash Ravine is renamed Eastwood Ravine.
- 9:00 a.m. Marty departs 1885 and finally returns to 1985.
- Tuesday, December 15: Doc and Clara are married. 
- Date unknown: Hill Valley Police Station is established.
- Date unknown: Doc is mocked when he tries to file a patent at the patent office.
- Date unknown: Hill Valley Stationers is established.
- Date unknown: Marty's grandmother and George's mother, Sylvia McFly is born.
- Date unknown: Marty's grandfather and Lorraine's father, Sam Baines, is born.
- Date unknown: Marty's grandmother and Lorraine's mother, Stella Baines, is born.
- Friday, April 6: The United States declares war on Germany. Due to hostility against German-Americans during World War I, Doc's father changes his family's name from "Von Braun" to "Brown". 
- Date unknown: Arthur McFly joins the U.S. Army and is shipped over to France, but is not sent into combat. When it is discovered that he is only 16 years old, he is sent home. 
- Date unknown: Grays, the future publisher of Grays Sports Almanac, is founded.
- Date unknown: Gerald Strickland is born.
- Date unknown: The ladder to the Courthouse was removed due to jumping incidents.
- Date unknown: A History of Hill Valley, 1850-1930 is published.
- Date unknown: At age 11, young Emmett Brown reads the works of Jules Verne for the first time and decides to dedicate his life to science.
- Monday, October 12: Due to changes made to the timestream, Arthur McFly and Sylvia Miskin get married. The first Hill Valley Science Exposition also began.
- Date unknown: At age 12, young Emmett tries digging to the center of the Earth, inspired by Verne’s Journey to the Center of the Earth.
- Date unknown: Goldie Wilson is born.
- Date unknown: The second Hill Valley Science Exposition is held.
- February: A building which eventually became Valley Video was built on the site of the Hill Valley speakeasy.
- Date unknown: Milton Baines is born to Sam and Stella Baines.
- Date unknown: Toby Baines is born to Sam and Stella Baines.
- Date unknown: Sally Baines is born to Sam and Stella Baines.
- Date unknown: 12-year-old George McFly tries standing up for his friend Billy Stockhausen, but fails to do so.
- Friday, February 15: Emmett Brown considers wrestling "Mad Maximus" but never shows up for the match. Following a visit by Marty, Jules and Verne, the timeline is altered and Brown acts as a vigilante crime fighter.
- Date unknown: Old Man Peabody tries to breed pine trees on his farm. He has a twin pine.
- Saturday, November 5:
- Marty McFly arrives from the year 1985 and disrupts the space-time continuum.
- Doc Brown slips off his toilet whilst hanging a clock and has a vision of the flux capacitor.
- Biff Tannen and his gang pick on George McFly at Lou's Cafe. Biff warns George never to go into Lou's Cafe again. Although Goldie Wilson urges George to stand up for himself, George ignores the advice.
- Sam Baines accidentally hits Marty with his car. When Marty recovers, he seeks out Doc Brown to help him get back to 1985.
- Saturday, November 12:
- Doc and Marty prepare for his return to 1985, unaware that older versions of themselves have arrived from the future, or that a much older Biff has arrived from the 21st Century, or that there are three DeLoreans in Hill Valley that day.
- Old Biff gives young Biff an almanac and departs that evening for 2015.
- George and Lorraine kiss for the first time at the Enchantment Under the Sea dance at Hill Valley High School. It is at that moment that Lorraine realizes that she is going to spend the rest of her life with George McFly.
- Marty retrieves the almanac from young Biff.
- Old Doc is accidentally sent back to 1885 by a lightning strike.
- 10:04 p.m.: Lightning strikes the clock tower at precisely 10:04 p.m., damaging and stopping the seven-decade-old timepiece, and sending young Marty McFly to 1985. A slightly older Marty arrives moments later, with a letter for young Doc.
- Wednesday, November 16: Doc sends Marty to 1885 in a newly repaired DeLorean.
- Date unknown: Ellen Baines is born to Sam and Stella Baines
- Date unknown: Lyon Estates, the future home of George and Lorraine McFly and their kids in 1985, is completed.
- Date unknown: George McFly and Lorraine Baines graduate from Hill Valley High School.
- Date unknown: George McFly and Lorraine Baines are married. Earliest possible time for them to move to Lyon Estates.
- Wednesday, August 1
- Timeline 1 (Original timeline before time travel)
- Timeline 2 (After using the temporal field capacitor)
- Doc receives a message from himself from two months into the future, delivered through time by his prototype temporal field capacitor. The build-up of flux energy created by sending an object so far into the past caused Doc's mansion to be destroyed by the resulting fire. The fireproof garage is the only surviving structure, and Doc moves into it.
- Timeline 8 (After Marty returns home) and 3-7, except 6 (Biff rewrites 1955)
- Doc receives a letter from his counterpart in the future, and the garage burns down. However, he now knows that he will successfully invent a time machine capable of transporting living beings, due to sending Marty through time in that machine. He now intends to use the money for multiple future inventions.
- Date unknown:
- Doc is awarded insurance money when the cause of the fire is deemed to be inconclusive.
- Wednesday, August 1
- Date unknown: Doc sells off the rest of the land, where his mansion was located before it burned down, to commercial developers. Only his garage remains.
- Date unknown: Ito Fujitsu is born.
- 1976 – 1977
- Date unknown: 12-year-old Marty McFly skateboards down the Courthouse steps, receiving a scar on his left knee.
- Date unknown: Marty and Doc meet and become friends. According to the original Part I script, Doc shows up at Marty's house and hires Marty to sweep his garage in the year 1983. Doc gave Marty total access to his record collection, and they became friends.
- Sunday, May 22: Ronald Reagan announces he will run for a second term in office. Although a newspaper headline, seen in Timeline 2, mentions that Doc Brown is commended and wins an award, it is unknown whether this happened in the original timeline (because in 1985, Dr. Brown is described (by Mr. Strickland) as "a real nutcase").
- Date unknown: Marty sneaks out of his house at night to meet his friends, and his mother hears the sound of a skateboard and catches him. Marty recalls the incident when he sneaks out again two years later. 
- June: Linda McFly graduates in the Class of '84.
- Saturday, October 12: Libyan terrorists steal plutonium from the local power plant so Doc can build them a nuclear weapon. It is dismissed by the FBI as a "simple clerical error". 
- Friday, October 25:
- 8:18 a.m. Openings titles of "Back to the Future." All the clocks are set 25 minutes slow, displayed incorrectly as 7:53 a.m.
- 8:25 a.m. Doc asks Marty to meet him at Twin Pines Mall at 1:15 a.m. next morning.
- Marty arrives to school late then fails his audition with his band, The Pinheads, later after school.
- Marty admires a black Toyota 4x4 on the bed of a truck at the Texaco gas station.
- A woman asks Marty for a donation to preserve the non-functioning clock tower, handing him a flyer containing specific date and time details about the lightning strike to the clock. Marty puts the flyer in his pocket.
- Lorraine's brother Joey fails to make parole again.
- Saturday, October 26:
- 12:28 a.m. Doc calls Marty to stop by at his garage to pick up his JVC camcorder.
- 1:16 a.m. Marty arrives at Twin Pines Mall.
- 1:18 a.m. Doc demonstrates Temporal Experiment #1.
- 1:20 a.m. Einstein becomes the first time traveler in the world by departing one minute into the future. (This time jump does not create a new timeline; timelines are only created by going back in time. Einstein merely moves 1 minute forward on Timeline 1. The Doc states this is the case with timelines in the blackboard scene in Part II.)
- 1:21 a.m. Einstein arrives at one minute into the future.
- 1:33 a.m. Doctor Emmett Lathrop "Doc" Brown is shot dead by Libyan terrorists.
- 1:35 a.m. Marty flees from the Libyans in the DeLorean and accidentally departs 1985 for 1955 by accelerating to 88 mph. His arrival there brings Timeline 2 into existence, and Timeline 1 fades from existence.
- Marty, 8 days older, arrives from 1955 and crashes into the front of the Assembly of Christ He then runs from the town square over to the Lone Pine Mall to witness the departure of his one-week-younger self, and sees the Libyans crash into a photo kiosk. Doc escapes injury and departs later that morning to go to the future.
- Marty wakes up at 10:28. Later that morning, Doc arrives and takes Marty and Jennifer to the future.
- Sunday, October 27:
- After arriving from 2015 to an altered timeline, Marty and Doc travel back to 1955 to right things.
- Marty, another week older, returns later that morning from 1885 and escapes injury when the time machine is destroyed.
- Marty picks up Jennifer. While they're stopped at a light, Needles tries to get Marty to race him. Marty declines.
- Doc and Clara arrive in 1985 and introduce their sons to Marty and Jennifer.
- October/November: George McFly's first novel, A Match Made in Space, is published.
- Doc Brown and his wife Clara settle down in Hill Valley, and enroll their children, Jules (10) and Verne (8), at the local elementary school.
- The Browns (Doc, Clara, Jules and Verne) see more of the Tannens (Biff and Biff, Jr.)
- Date unknown: Roberta Needles, older daughter of Douglas Needles, is born.
- Date unknown: Amy Needles, younger daughter of Douglas, is born.
- Date unknown: The Hill Valley Telegraph closes or sells its printing and news-gathering operations to USA Today to create a local edition of the nationwide newspaper.
- Date unknown: Invention of hover conversion, Mr. Fusion, the Black & Decker hydrator, hoverboards, power shoelaces and auto-drying jackets, skyways, rejuvenation clinics, suspended animation kennel, automated gas stations, automatic dog-walkers, portable thumb units, the multi-channel video screens, automated hovering news units (as used by USA Today), roll-down television sets (the McFly home runs The Scenery Channel on it in a window).
- Date unknown: The United States abolishes the trade of lawyers, allowing the justice system to move with far greater speed and efficiency.
- Date unknown: With the justice system operating more quickly and efficiently, the Clock Tower courthouse is converted into Hill Valley Courthouse Mall, complete with a glass center facade. Thanks to the continuing efforts of the Hill Valley Preservation Society, the 130-year-old clock remains stuck at 10:04 (along with the burnt lightning rod above it and the damaged ledge below it).
- Date unknown: The US Weather Service develops the ability to either end or predict the end of rainfall to the exact second.
- Date unknown: Relations with Vietnam improve and now there are promotions to surf there.
- Date unknown: Pepsi introduces Pepsi Perfect, a vitamin enriched cola (Marty orders this from the video waiter at the Cafe 80's).
- Date unknown: Pizza Hut introduces the dehydrated pizza that Lorraine McFly cooks in the hydrator.
- 2009 or 2013
- Date unknown: A woman becomes President of the United States (she is mentioned in the 2015 newspaper).
- Doc spends an unknown amount of time in 2015 and later. While he's there, he places Einstein in a suspended animation kennel, outfits the time machine with a Mr. Fusion and a hover conversion, undergoes personal rejuvenation surgery, and learns as much as he can about Marty Jr.'s meeting with Griff on the 21st. Eventually, Doc leaves for 1985 to fetch Marty and Jennifer.
- Date unknown: Jaws 19 debuts at the theater: this time, it's really really personal.
- Wednesday, October 21: The Chicago Cubs win baseball's World Series in a 5 game sweep over Miami.
- Friday, October 23: Queen Diana visits Washington according to the October 22 issue of USA Today.
- Date unknown: Ziff Tannen, grandson of Griff Tannen, is born.
- Date unknown: Marta McFly, granddaughter of Marty McFly Jr., is born.
- June 3: The Brown family and Marty travel to 2585 and witness the robot revolution. 
- Date Unknown: The Brown family and Marty accidentally arrive here from 2585 after the time train malfunctions. 
- ↑ From the animated episode Roman Holiday
- ↑ from the animated episode, Put on Your Thinking Caps, Kids! It's Time for Mr. Wisdom!
- ↑ from the animated episode, A Family Vacation
- ↑ from the animated episode, Time Waits for No Frog
- ↑ from the animated episode Witchcraft
- ↑ from the animated episode Mac the Black
- ↑ from the animated episode, Go Fly a Kite
- ↑ from the animated episode, Einstein's Adventure
- ↑ from the animated episode, Dickens of a Christmas
- ↑ from the animated episode, Clara's Folks
- ↑ Back to the Future Part II: The money was visible in Doc's suitcase.
- ↑ from the animated episode, Brothers
- ↑ Historical fact. See From the Earth to the Moon for details. The book is mentioned in Back to the Future Part III.
- ↑ based on an 1885 issue of the Hill Valley Telegraph that commemorates the 20th anniversary of the event
- ↑ Clara mentions this in conversation with Doc in Back to the Future Part III
- ↑ Historical fact. See Twenty Thousand Leagues Under the Sea for details. The book is mentioned in Back to the Future Part III.
- ↑ from the animated episode, Put on Your Thinking Caps, Kids! It's Time for Mr. Wisdom!
- ↑ Back to the Future Part II: Doc and Marty read the newspaper in 1955.
- ↑ 19.0 19.1 19.2 Back to the Future Part III: Part of Doc's letter.
- ↑ Back to the Future Part III: The clock was seen in the background at the train station in 1885.
- ↑ from the animated episode, Solar Sailors; Doc and Clara are celebrating their anniversary on December 15, 1991, and Doc jokes that they've been married almost 106 years.
- ↑ conjecture from Jules being two years older than Verne, and that he was conceived after his parents' marriage.
- ↑ from the animated episode, "By Any Other Name"
- ↑ Back to the Future: Untold Tales and Alternate Timelines: Issue 5 - "Clara's Story"
- ↑ The animated series episode St. Louis Blues. The first issue of the Harvey comic series established that Doc and Clara keep a part time residence in the 19th century.
- ↑ from the animated episode, Batter Up
- ↑ Marty mentions this family story to George in 1955 (BTTF novelization, p91, although this is not seen in the film.
- ↑ 28.0 28.1 Back to the Future Part III: Doc tells Marty about it in 1955.
- ↑ BTTF novelization, p91
- ↑ based on a mention in the BTTF novel that in 1985, Doc is 65 years old. However, the animated episode Gone Fishin' says that Doc was born in 1922. Neither date can be inferred from the film trilogy.
- ↑ Historical fact. See Clint Eastwood for details.
- ↑ as established in Back to the Future Part II, which recounts Biff's life story and "how a trip to the races on his 21st birthday made him a millionaire overnight," and shows a newspaper dated March 27, 1958
- ↑ as seen on George's tombstone in 1985A in Back to the Future Part II; names of parents are from the BTTF novel at page 91
- ↑ from DVD commentary by Bob Gale in Back to the Future
- ↑ Back to the Future. Doc tells Marty about this in the parking lot of Twin Pine Mall in 1985, and the farm is seen when Marty gets in 1955.
- ↑ 36.0 36.1 Back to the Future Part I. Doc tells Marty about this in the parking lot of Twin Pine Mall in 1985.
- ↑ Historical fact. See history of Toyota for details.
- ↑ Historical fact. See Johnny B. Goode for details.
- ↑ Back to the Future Part II. Mentioned in the video presentation on the life of Biff in the Biff Tannen museum, in the alternate 1985.
- ↑ Historical fact. See Tab (soft drink) for details.
- ↑ Historical fact. See Studebaker's exit from the auto business for details.
- ↑ Historical fact. See A Fistful of Dollars for details. The film is depicted in Back to the Future Part II and homaged in Back to the Future Part III.
- ↑ Bob Gale referred to the date in a draft screenplay for Part II, although this did not end up in the film trilogy, the novelizations, or the animated series
- ↑ Cite error: Invalid
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- ↑ from Back to the Future
- ↑ Historical fact. See Caffeine-Free Pepsi for details.
- ↑ Novelization, p44
- ↑ Back to the Future. According to a TV news program heard in the background.
- ↑ As seen in Harvey Comics #5.
- ↑ As seen in Harvey Comics #6.