Seahenge was an archaeological site found during exceptionally low tides on the coast at Holme in Norfolk. It consisted of a circle of wooden posts surrounding an upturned tree stump, dating from the bronze age. Shortly after its discovery by archaeologists it was dug up and placed in the museum at Flag fen. This was controversial. The archaeologists claimed that the henge was in imminent danger of distruction. Local people had been aware of the henge for decades. The bulk of the structure was buried in anaerobic clay. Only the top few inches were visible. The removal of the henge provoked direct action protests and police were required to allow the excavation to go ahead.

Seahenge is at the Northernmost point of the Icknield Way. It would have been inland at the time of its construction. A similar structure has apparently been found in the Humber estuary, but this has received less publicity.