|Length:||37.1 miles (59.7 km)|
|Met (1923):||A88, B871, B870|
|Now part of:||A897|
|Route outline (key)|
The original route of the B872 crossed from Helmsdale on the southern coast of Sutherland to Melvich on the north coast. It now carries the A897 number, the change happening sometime between 1932 and 1935.
Starting on the A88 (present A9) in Helmsdale the road headed upstream along the Strath of Kildonan, the valley of the River Helmsdale. The B872 remained on the left bank of the river with the railway line keeping it company on the other bank. After some distance road and railway both left the Helmsdale behind and crossed a saddle before reaching Strath Beg, a tributary, and the B871 at Kinbrace.
The road and railway line ran next to each other across Achentoul Forest, after which they crossed at Forsinard, with the railway line now heading off east whilst the B872 continued ahead. It descended Strath Halladale alongside the river of that name, presently crossing it. A few more miles downstream the road reached its terminus on the B870 (present A836 opposite Melvich and only a mile from the north coast.