|Location Map ( geo)|
|From:||Milltown of Campfield (NJ648003)|
|To:||Bridge of Canny (NO644976)|
|Distance:||2 miles (3.2 km)|
|Met:||A980, C20M, C4K|
|Now part of:||C4K|
|Route outline (key)|
The C21M started on the A980 at Milltown of Campfield and headed south, past Glassel, to meet the C20M a short distance west of Bridge of Canny. It also appears to have had a short spur eastwards at Glassel to the county boundary, where it met the C4K. The two routes have since been combined, as the C4K.