Notable archaeological sites include the Iron Age hill forts at Membury Castle, Hembury and Castle Neroche. Hembury is a Neolithic causewayed enclosure near Honiton. It dates to the late fifth and early fourth millennia BC and is believed to have been the capital of the Dumnonii tribe. The fort is situated on a promontory to the north of and overlooking the River Otter, Devon at approx above sea level. It has given its name to some of the earliest Neolithic pottery in southern Britain. An Iron Age hill fort was later built on the same site.