Thornton is an unincorporated place in Essa Township, Simcoe County, Ontario, Canada.

The town of Thornton developed during the 1820s, and in 1833 was established as Henrysville (or Henry's Corners) after early settler John Henry, who was the first teacher and then the schoolmaster, and later became the postmaster when an office opened in 1854.

As of January 2019, there is a new residential subdivision of estate homes currently under development on the west side of Hwy.

Thornton is located on generally flat[citation needed] and fertile soils about 9 kilometres (5.6 mi) north of Cookstown, Ontario, and 5 kilometres (3.1 mi) south of Barrie, Ontario.

1 Separated municipalities but remain a census subdivision of the county