Jacksonville is the most populous city proper in the U.S. state of Florida, located on the Atlantic coast of northeastern Florida. It is the seat of Duval County, with which the City of Jacksonville consolidated in 1968. It is the largest city by area in the contiguous United States as of 2020.

Florida's First Coast, or simply the First Coast, is a region of the U.S. state of Florida, located on the Atlantic coast of North Florida. The First Coast refers to the same general area as the directional region of Northeast Florida. It consists roughly of the counties abutting Jacksonville—Duval, Baker, Clay, Nassau, and St. Johns—and nearby Flagler County and Putnam County. The name originated in a marketing campaign in the 1980s, and has become part of Florida's regional vernacular.