Mount Croghan is a town in Chesterfield County, South Carolina, United States. The population was 195 at the 2010 census, up from 155 in 2000. Mount Croghan is located in northern Chesterfield County at 34°46′7″N 80°13′31″W / 34.76861°N 80.22528°W. South Carolina Highway 9 passes through the town, leading east 9 miles to Chesterfield, the county sea…Mount Croghan is a town in Chesterfield County, South Carolina, United States. The population was 195 at the 2010 census, up from 155 in 2000. Mount Croghan is located in northern Chesterfield County at 34°46′7″N 80°13′31″W / 34.76861°N 80.22528°W. South Carolina Highway 9 passes through the town, leading east 9 miles to Chesterfield, the county seat, and west 9 miles to Pageland. South Carolina Highway 109 leads north from Mount Croghan 3 miles to the North Carolina border, from where North Carolina Highway 109 leads northeast another 14 miles to Wadesboro. SC 109 joins SC 9 running east from Mount Croghan 3 miles to Ruby. South Carolina Highway 268 leads southwest from Mount Croghan 13 miles to Jefferson.