Hialeah (pronunciation: /ˌhaɪəˈliːə/) is a city in Miami-Dade County, Florida, United States. As of the 2010 census, Hialeah has a population of 224,669. Hialeah is the sixth-largest city in the state, and is a major city within the South Florida metropolitan area. It is located west-northwest of Miami, and is the only place in the county to have its own street grid numbered separately the rest of the county (which is otherwise based on Biscayne Boulevard at Flagler Avenue in downtown Miami, the county seat).