Fairfield County is a county in the southwestern corner of the U.S. state of Connecticut. It is the most populous county in the state and was also its fastest-growing from 2010 to 2020. As of the 2020 census, the county's population was 957,419, representing 26.6% of Connecticut's overall population. The closest to the center of the New York metropolitan area, the county contains four of the state's seven largest cities—Bridgeport (first), Stamford (second), Norwalk (sixth) and Danbury (seventh)—whose combined population of 433,368 is nearly half the county's total population.
The United States Office of Management and Budget has designated Fairfield County as the Bridgeport–Stamford–Norwalk metropolitan statistical area. The United States Census Bureau ranked the metropolitan area as the 59th most populous metropolitan statistical area of the United States in 2019. The U.S. Office of Management and Budget has further designated the metropolitan statistical area as a component of the more extensive New York–Newark–Bridgeport, NY–NJ–CT–PA combined statistical area, the most populous combined statistical area and primary statistical area of the United States.