Mainsforth is a small village and former civil parish, now in the parish of Bishop Middleham, in the County Durham district, in the ceremonial county of Durham, England.

It has been suggested, without great historical foundation, that this was a Danish settlement.

Mainsforth Hall was a significant building in the centre of this small village, until its demolition in the 1960s.

A notable member of the family was Robert Surtees (1779–1834), a County Durham historian.

[3] Mainsforth Colliery, active from 1872-1968, lay between the village and Ferryhill Station.