Southminster is a town and electoral ward on the Dengie Peninsula in the Maldon district of Essex in the East of England. It lies about 3 miles (4.8 km) north of Burnham-on-Crouch and 10 miles (16 km) south-east of Maldon; it is approximately 52 miles (84 km) east-north-east of London. To the north is the River Blackwater, which is tidal, and, since Roman times, has been the gateway to trading in the area.