History:

Located four miles south of Rockland.  Indian name, "Wessaweskeag," afterward contracted to "Weskeag," and afterward to "Keag."  First settled 1776, by Elisha Snow, from Harpswell, John Matthews, of Plainfield, Connecticut, and Stephen Peabody, of Middleton, Massachusetts, who settled at Owl's Head.  Set off from Thomaston, and incorporated July 28, 1848.

There were two stages daily from Clark Island and Spruce Head via. South Thomaston to Rockland, and two stages from South Thomaston to Rockland.

The area of present day South Thomaston along the St. George River was actually settled before the year 1776.  This area was first settled in 1765 by Samuel Brown and Oliver Robbins.  South Thomaston is credited with being first settled in 1776, because the area on the northeastern side of the Wessaweskeag River is what was considered to be South Thomaston during that time.

Owl's Head was set off from South Thomaston by act of legislature, April 9, 1921.

Population of South Thomaston in 1990 was 1,227 and in 2000 was 1,416.