Mareham on the Hill is a village and civil parish about 2.5 miles (4.0 km) south-east from the town of Horncastle, Lincolnshire, England.

Mareham on the Hill is listed in the 1086 Domesday Book as having one household and 8 acres (0.032 km2) of woodland.

[2] The parish church is dedicated to All Saints and is a Grade II* listed building dating from the 15th century, although it was restored in 1780 and remodelled in 1804.

It is built of green sandstone, limestone and red brick, and is colourwashed.

The 2013 incumbent is Rev Canon Alec Boyd.