South Portsmouth is an unincorporated community in Greenup County, Kentucky, United States. South Portsmouth is located on the Ohio River across from Portsmouth, Ohio and 3 miles west of South Shore, Kentucky. Kentucky Route 8 passes through the community.South Portsmouth was originally called Springville due to the numerous springs in the area. Springville was incorporated as a town on March 3, 1876. The Chesapeake and Ohio Railroad built a track through the community in the early 1900s. Subsequently the name of the community was changed to South Portsmouth, presumably to indicate its location with respect to Portsmouth, Ohio.