Located in the southwestern part of the state, the district is largely suburban and extends from Bridgeport, the largest city in the state, to Greenwich – an area largely coextensive with the Connecticut side of the New York metropolitan area.

With a Cook Partisan Voting Index rating of D+13, it is the most Democratic district in Connecticut, a state with an all-Democratic congressional delegation.

This culminated in 2020, when Joe Biden won it with 64 percent of the vote, his best showing in the state.

In 2004, however, Democrat Diane Farrell held longtime incumbent Chris Shays to only 52 percent of the vote, the closest race in the district in 30 years.

For the 118th and successive Congresses (based on redistricting following the 2020 census), Connecticut's 4th district contains portions of three planning regions and 18 municipalities.