Mobile is the county seat of Mobile County, Alabama, United States. The population within the city limits was 195,111 as of the 2010 United States Census, making it the third most populous city in Alabama, the most populous in Mobile County, and the largest municipality on the Gulf Coast between New Orleans, Louisiana, and St. Petersburg, Florida.Alabama's only saltwater port, Mobile is located on the Mobile River at the head of the Mobile Bay and the north-central Gulf Coast. The Port of Mobile has always played a key role in the economic health of the city, beginning with the settlement as an important trading center between the French colonists and Native Americans, down to its current role as the 12th-largest port in the United States.Mobile is the principal municipality of the Mobile metropolitan area. This region of 412,992 residents is composed solely of Mobile County; it is the third-largest metropolitan statistical area in the state.