One Tree Hill is part of the Langdon Hills County Park which can be accessed from the A13.
Directions from Colchester
Follow A12 along Chelmsford By-Pass to A130
Follow A130 south (signposted Basildon/Southend) and onto A13 towards London
Head towards London on A13 to junction with A176
Follow roads parallel to A13 (B1420) to junction with “One Tree Hill”. Turn right here (passes back over the A13)
Follow for about half a mile and the entrance is on the left