Mountain Park is a city primarily in the western part of northern Fulton County in the U.S. state of Georgia, with a small portion extending le…Mountain Park is a city primarily in the western part of northern Fulton County in the U.S. state of Georgia, with a small portion extending less than 1,000 feet into southeastern Cherokee County. As of the 2020 U.S. census, the city had a total population of 583.