The hillfort is situated on a broad northerly spur at the summit of Lambert's Castle Hill, which rises to a height of . There are steep natural slopes on three sides of the fort, and linear ramparts across the flat southern approaches. The site is owned by the National Trust. A car park is accessible from the B3165 road. There are two other hill-forts near Lambert's Castle: Coney's Castle is about to its south, and Pilsdon Pen is about to its north-east.