Castle Hill is something that I have seen many times over the years as I pass through Mere, or pass by on the busy A303. It is a very prominent landmark, rising up on the north edge of the town and overlooking the settlement on one side, and the downs to the north.
From some angles it looks man made, and reminded me of Silbury Hill but I've not found any evidence that it is. There used to be a castle on the summit, built in 1253 by Richard, Earl of Cornwall but it has long since disappeared and only the earthworks remain.
The land around here is owned by the Duchy of Cornwall, and the hill is leased to the parish council of Mere. It is a steep walk to the top, but the summit is flat and has benches around each side allowing you to get a good panoramic view of the local area. There is a flagpole at the top flying the flag of England and a memorial to the 43rd (Wessex) Infantry Division.
There is a car park in the centre of Mere close to the Church. The hill is easily accessible from there via multiple paths that lead you to the base of it. It is steep, but a short walk to the summit.
The video below gives a fabulous panoramic of the hill and the whole town, offering glimpses into the surrounding countryside.