Marnhull is sited on a low ridge of Corallian limestone[1] above the valley of the River Stour, which forms the northern and western boundaries of the parish.

The village presents a mix of architectural styles, with post-war developments existing alongside properties dating back to Tudor times and earlier.

It has three churches (Anglican, Roman Catholic and Methodist), two primary schools, two public houses, a GP surgery, a village hall and a recreation ground, as well as various small shops and services.

The Domesday Book of 1086 does not mention Marnhull by name, though the constituent settlements of Walton Elm, Burton and Kentleworth were probably recorded under the entry for Sturminster Newton as the eight hides of land owned by Waleran, Roger and Chetel.

Marnhull village is sited on the ridge of Corallian beds, which form the highest part of the parish and are the source of the building stone extensively used throughout it.