|Location Map ( geo)|
|Distance:||3.3 miles (5.3 km)|
|Route outline (key)|
The C66 starts on the A68 on the north side of Ancrum Park and heads west, turning north west as it loosely follows the north side of the fairly flat valley of the Ale Water. After passing a handful of properties, the route comes to an end on the C52 at Longnewton.