Fountain City is a neighborhood in northern Knoxville, Tennessee, in the southeastern United States. Although not a census-designated place (it is grouped with Knoxville for census-purposes), the populations of the two ZIP codes that serve Fountain City— 37918 and 37912— were 36,815 and 18,695, respectively, as of the 2000 U.S. census.[1][2] At the time of its annexation by the city of Knoxville in 1962, Fountain City was the largest unincorporated community in the United States.[3]