About 6,000 Indians inhabited Connecticut at the time Europeans arrived. All belonged to tribes of the Algonquian language family. Most of the tribes lived by hunting and fishing and had occupied the same settlements for centuries. The warlike Pequots and Mohegans, however, were nomads. They arrived long after the other tribes and were greatly feared by them.
| Important dates in Connecticut | |
| 1614 | Adriaen Block claimed Connecticut for the Dutch. |
| 1633 | The first English settlement in Connecticut was made in Windsor. |
| 1636 | The towns of Hartford, Wethersfield, and Windsor united to form the Connecticut Colony. |
| 1637 | Connecticut and other colonies defeated the Pequot Indians in the Pequot War. |
| 1638 | A group of wealthy Puritans founded New Haven. |
| 1639 | The Connecticut Colony adopted the Fundamental Orders. |
| 1662 | The Connecticut Colony received a charter from England. This charter served as Connecticut's constitution until 1818. |
| 1665 | The Connecticut and New Haven colonies united. |
| 1687 | Colonists preserved the Connecticut charter by hiding it, presumably in the Charter Oak in Hartford. |
| 1776 | Connecticut passed a resolution in favor of independence from Britain on June 14. |
| 1788 | Connecticut became the 5th state when it ratified the U.S. Constitution on January 9. |
| 1910 | New London became the home of the U.S. Coast Guard Academy. |
| 1954 | The Nautilus, the first nuclear-powered submarine, was built and launched in Groton. |
| 1965 | Connecticut apportioned its legislative districts on the basis of population. Connecticut adopted a new constitution. |
| 1979 | Connecticut passed a law banning the construction of additional nuclear power plants. Existing plants were allowed to continue operating. |
| 1991 | Connecticut established an individual income tax to raise additional state revenue. |
