 Somerset is a rural county in the southwest of England , covering 4 @,@ 171 square kilometres ( 1 @,@ 610 sq mi ) . It is bounded on the north @-@ west by the Bristol Channel , on the north by Bristol and Gloucestershire , on the north @-@ east by Wiltshire , on the south @-@ east by Dorset , and on the south west and west by Devon . It has broad central plains with several ranges of low hills . The landscape divides into four main geological sections from the Silurian through the Devonian and Carboniferous to the Permian which influence the landscape , together with water @-@ related features . 
