Colsterworth is raised upon a slight limestone ridge, with the River Witham running below on the western side and dividing the two villages. The old hamlet of Twyford has been incorporated by the growth of Colsterworth, but the name survives in the names of some houses and in Twyford Wood. The area between Colsterworth Church and Twyford was once known as Dunkirk. Colsterworth, Woolsthorpe and Twyford are all separately entered in the "Domesday Book" of 1086. The village belonged to the historical wapentake of Winnibriggs and Threo.