Various tribes lived in or around Hartford, all Algonquian peoples. These included the Podunks, mostly east of the Connecticut River; the Poquonocks north and west of Hartford; the Massacoes in the Simsbury area; the Tunxis tribe in West Hartford and Farmington; the Wangunks to the south; and the Saukiog in Hartford itself.

Hartford was founded in 1635 and is among the oldest cities in the United States. It is home to the country's oldest public art museum (Wadsworth Atheneum), the oldest publicly funded park (Bushnell Park), the oldest continuously published newspaper (the Hartford Courant), and the second-oldest secondary school (Hartford Public High School).

When Puritan pastors Thomas Hooker and Samuel Stone, along with Governor John Haynes, led 100 settlers on a trek from Newtown in the Massachusetts Bay Colony (now Cambridge) and started their own settlement, they originally called it Newtown as well, but the name was changed to Hartford in 1637 in honor of Stone's hometown of Hertford, England.

30 years before the Salem witch trials, hysteria, accusations, and trials rattled Hartford in what was the nation's first witch hunt. The Connecticut Witch Trials, also sometimes referred to as the Hartford witch trials, occurred from 1647 to 1663. Eleven women and men were executed, beginning with Alice Young. Her hanging in Hartford on May 26, 1647, was the first witchcraft execution to occur in America.

Hartford is home to the Mark Twain House, where the author wrote his most famous works, including The Adventures of Huckleberry Finn, and raised his family. In 1868, Mark Twain wrote of Hartford: "Of all the beautiful towns it has been my fortune to see this is the chief."

Hartford is home to the headquarters of more than 100 insurance companies, earning it the title of "Insurance Capital of the World". Companies like Aetna, Conning & Company, The Hartford, Harvard Pilgrim Health Care, The Phoenix Companies, and Hartford Steam Boiler are based in the city, and companies such as Prudential Financial, Lincoln National Corporation, Travelers, United Healthcare and Axa XL have major operations in the city.

In 1997, the city lost its professional hockey franchise, when the Hartford Whalers relocated to North Carolina, where they became the Carolina Hurricanes.

The Charter Oak was an unusually large white oak tree growing on Wyllys Hyll in Hartford, from around the 12th or 13th century until it fell during a storm in 1856. According to tradition, Connecticut's Royal Charter of 1662 was hidden within the hollow of the tree to thwart its confiscation by the English governor-general. The oak became a symbol of American independence and is commemorated on the Connecticut State Quarter.

"Hartford is where I learned to grow up," Katharine Hepburn revealed in 1988. "It is where I will come home to." After her death in 2003, she did just that. The Oscar winner's remains were buried in the Hepburn family plot at Hartford's Cedar Hill Cemetery.

Samuel Colt was born in Hartford in 1814. In 1836, at the age of twenty-two, he received a U.S. patent for a revolver mechanism which enabled a gun to be fired multiple times without reloading. Sales were initially slow and his business ventures struggled, until the U.S. government ordered 1,000 Colt revolvers for use in the Mexican-American War. With these funds, Colt was able to salvage his business, which he converted it into a corporation in 1855 under the name of Colt's Patent Fire Arms Manufacturing Company. The original factory is situated in the Sheldon/Charter Oak neighborhood just south of downtown Hartford.