Lambert's Castle Hill (258 metres, 846 feet high) rises between the villages of Marshwood and Fishpond Bottom in the county of Dorset, England.

It is part of the South Dorset Downs and its prominence qualifies it as one of the so-called HuMPs.

[1] In his book, The Highways and Byways of Dorset, Treves writes "Lambert’s Castle is a fine ridge, terminating in a truculent headland distinguished by a clump of fir trees.

From hence can be seen Portland, the sea breaking on the Chesil Beach, the Fleet, a long stretch of the Devon coast and far inland, the uplands of Wiltshire and Somerset.

The hilltop was used as a racecourse at some stage and was also the site of a fair for over 200 years.