Afton is a city in Washington County, Minnesota, United States. The population was 2,886 at the 2010 census. It is located on a small bay where Valley Creek empties into the St. Croix River several miles north of the confluence with the Mississippi River.Afton is well known for Afton Alps, the largest ski and snowboard area in the Twin Cities metropolitan area. It is also home to Afton State Park, a popular park on the St. Croix River. Due to these two destinations and the quaint small-town appearance in a major metropolitan area, Afton receives a fair amount of local tourism in the form of day trips.