The Somerset Coalfield in northern Somerset, England is an area where coal was mined from the 15th century until 1973. It is part of a larger coalfield which stretched into southern Gloucestershire. The Somerset coalfield stretched from Cromhall in the north to the Mendip Hills in the south, and from Bath in the east to Nailsea in the west, a total area of about 240 square miles (622 km2). Most of the pits on the coalfield were concentrated in the Cam Brook, Wellow Brook and Nettlebridge Valleys and around Radstock and Farrington Gurney. The pits were grouped geographically, with clusters of pits close together working the same coal seams often under the same ownership. Many pits shared the trackways and tramways which connected them to the Somerset Coal Canal or railways for distribution.