New Haven was founded in 1638 by a group of about 500 Puritans who left the Massachusetts Bay Colony in search of a more "perfect" place to worship. The town was originally named Quinnipiac, after the Indians who lived in the region, but was renamed New Haven in 1640. In 1664, New Haven became part of the Connecticut Colony, and was made co-capital in 1701 (it maintained this status until 1873). In 1716, Yale University moved from Old Saybrook to New Haven. Today, it is one of the nation’s most prestigious universities.

On April 23, 1775, the Governor’s foot guard, a division of the Connecticut militia under the command of future traitor Benedict Arnold, demanded the keys to the Powder House (a place where guns and ammunition were stored) to arm themselves before marching to Cambridge, Massachusetts. Word of the Battles of Lexington and Concord had just reached Connecticut, and the soldiers wanted to join the budding revolution. The event is still celebrated as Powder House Day in New Haven.

In 1792, Yale graduate Eli Whitney invented the cotton gin in New Haven – which made cotton processing 50 times more productive but also increased the demand for slaves.