Bokel Castle, Archaeological site in Lower Saxony, Germany.

Bokel Castle is a former oval ringwork in Bokel, Wiefelstede, Lower Saxony. Its double rampart and ditch enclosed an area of 55 by 65 metres within an outer diameter of 102 metres; the ramparts were built of sand covered with turf sods and topped by a palisade on the inner wall. The gate lay in the northeast toward the Friesische Heerstraße. About half of the ringwall survives.

The oval ringwork was built around 850 AD near the Friesische Heerstraße, making it the oldest surviving fortification in Ammerland. No written record of it exists; excavation inside the enclosure showed intensive use from the 9th to the 10th century and sporadic use into the 11th. By 1831, when C.F.A.O. von Negelein surveyed it, much of the rampart had been levelled; the double rampart was extensively restored in 1989.

Local legend gives the site its name in stories: a treasure lies hidden in the Bokeler Burg, guarded by spirits and unreachable all year. Only on Midsummer Night, 23 to 24 June, does it rise to the surface in a hollow to be bleached. Whoever lays inherited iron over it and stays silent may carry it home.

The site is accessible year-round for visitors to explore, though wet and muddy conditions can make walking difficult during wetter months. Sturdy footwear is recommended to navigate the uneven ground safely.

Legend says a treasure lies hidden in the Bokeler Burg, guarded by spirits and unreachable all year; only on Midsummer Night, from 23 to 24 June, does it rise into a hollow to be bleached. Whoever lays inherited iron over it and stays silent may carry it home, as the tale of the farmhand Gerken recounts.