Demopolis is the largest city in Marengo County, Alabama, United States. At the 2000 census the population was 7,540. History Demopolis, the City of the People, was founded by a group of French expatriates, many of whom came to the United States after fleeing a slave rebellion on the sugar plantations of Haiti.Blaufarb, Rafe. "Bonapartists in the Borderlands: French Exiles and Refugees on the Gulf Coast, 1815-1835." Tuscaloosa: University of Alabama Press, 2006. Arriving first in Philadelphia,… (More on Demopolis)