A hill is classified as a County Top if is the highest point in a county. These include all sort of hill including the highest in the UK (Ben Nevis, 1344m) and the lowest in our database (Pinchbeck Marsh, 8m).
The definition of "county" varies so the database divides up County Tops thus:
County Top - Administrative - the highest point in an area currently administered by a county council. There are currently 67 of these.
County Top - Historic - the highest point in a geographic county (often these have been broken up totally or partially into Unitary Authorities for administrative purposes. There are currently 94 of these.
County Top - London Borough - the highest point in a London Borough. There are currently 32 of these.
Twin County Top - London Borough - the highest point in two London Boroughs. There are currently 4 of these.
County Top - Current County and Unitary Authority - the highest point in a county and unitary authority area. There are currently 174 of these.
Twin County Top - Current County and Unitary Authority - the highest point in two county and unitary authority areas. There are currently 6 of these.
Unsurprisingly some hills fall into several of these classifications.