Southwestern Connecticut is part of the New York metropolitan area; three of Connecticut's eight counties, including most of the state's population, are in the New York City combined statistical area, commonly called the Tri-State Region. Connecticut's center of population is in Cheshire, New Haven County.

Connecticut is the 29th most populous state, with 3.5 million residents, and is ranked 48th in size by area, making it the 4th most densely populated state. Called the Constitution State and the Nutmeg State, Connecticut has a long history dating from early colonial times and was influential in the development of the federal government of the United States.

Connecticut's first European settlers were Dutch and established a small, short-lived settlement in present-day Hartford at the confluence of the Park and Connecticut rivers, called Huys de Goede Hoop. Initially, half of Connecticut was a part of the Dutch colony, New Netherland, which included much of the land between the Connecticut and Delaware rivers.

The first major settlements were established in the 1630s by the English. Thomas Hooker led a band of followers overland from the Massachusetts Bay Colony and founded what would become the Connecticut Colony; other settlers from Massachusetts founded the Saybrook Colony and the New Haven Colony. Both the Connecticut and New Haven Colonies established documents of Fundamental Orders, considered the first constitutions in North America. In 1662, the three colonies were merged under a royal charter, making Connecticut a crown colony. This colony was one of the Thirteen Colonies that revolted against British rule in the American Revolution.

Connecticut enjoys a temperate climate due to its long coastline on Long Island Sound. This has given the state a strong maritime tradition. Modern Connecticut is also known for its wealth. In the 18th and 19th centuries, Connecticut had ready access to raw materials which helped to develop a strong manufacturing industry, and financial organizations flourished: first insurance companies in Hartford, then hedge funds in Fairfield county. This prosperity has helped give Connecticut the highest per capita income, Human Development Index (0.962), and median household income in the country.

Connecticut is bordered on the south by Long Island Sound, on the west by New York State, on the north by Massachusetts, and on the east by Rhode Island. The state capital is Hartford, and the other major cities (by population) include Bridgeport, New Haven, Stamford, Waterbury, Norwalk, Danbury, New Britain and Bristol. There are 169 incorporated towns in Connecticut.

The highest peak in Connecticut is Bear Mountain in Salisbury in the northwest corner of the state. The highest point is just east of where Connecticut, Massachusetts, and New York meet (42° 3' N; 73° 29' W), on the southern slope of Mount Frissell, whose peak lies nearby in Massachusetts.

The Connecticut River cuts through the center of the state, flowing into Long Island Sound, Connecticut's outlet to the Atlantic Ocean.

Despite its size, the state has regional variations in its landscape and culture from the estates of Fairfield County's "Gold Coast" to the rolling mountains and horse-farms of the Litchfield Hills of northwestern Connecticut. Connecticut's rural areas and small towns in the northeast and northwest corners of the state contrast sharply with its industrial cities, located along the coastal highways from the New York border to New Haven, then northward to Hartford, as well as further up the coast near New London. Many towns center around a "green", such as the New Haven Green, Litchfield Green, Simsbury Green, Lebanon Green (the largest in the state), and Wethersfield Green (the oldest in the state). Near the green typically stand historical visual symbols of New England towns, such as a white church, a colonial meeting house, a colonial tavern or "inne", several colonial houses, etc., establishing a scenic historic appearance maintained for both historic preservation and tourism.

Due to the climate, degree of urbanization, and economic status of the state, it offers easily accessed forests, rivers, lakes, waterfalls and a coastline, all developed for recreation.