Caistor is a small town in the West Lindsey district, 11 miles W of the coast at Grimsby and 15 miles SE of Scunthorpe. As its name suggests it was a Roman camp and parts of the Roman walls survive. The church is in the centre of the town, on the site of the Castrum. It consists of a W tower, 11thc in origin; a nave with 11thc work at the W end but with later additions including 13thc N and S aisles, and a 15thc clerestorey; a 13thc S transept; and a chancel rebuilt in 1848, with a 13thc chancel arch and N and S chapels with 13thc entrance arches. The W tower has an early Romanesque W doorway. The church was restored by Butterfield in 1862.

The Domesday Survey records that Caistor was held by Earl Morcar before the Conquest, and by the King in 1086. It was assessed at 6 carucates and also included 60 acres of meadow, 4 mills a church and a priest. The population totalled 53 households.

By 1197-98 it was a prescriptive borough. A market was recorded from 1179 onwards.

The W tower doorway is apparently a later addition to the Anglo-Saxon tower, and is now squeezed between two 14thc buttresses.