St Just in Penwith (or St Just) is a town and parish in the far west of Cornwall, United Kingdom. The parish includes the town of St Just and the nearby settlements of Trewellard, Pendeen and Kelynack: it is bounded by the parishes of Morvah to the north-east, Sancreed and Madron to the east, St Buryan and Sennen to the south and by the sea in the west. The town of St Just is the most westerly town in mainland Britain and is about eight miles (12.7 km) west of Penzance along the A3071 road. St Just parish has a population of 4690. The parish church is a fine 15th century building. 