The B6404 is a secondary route in southeast Scotland. It was originally unclassified but gained its number in the late 1920s.
The road starts on the A68 opposite the Buccleuch Arms and heads northeast along Main Street. After crossing an expanse of grass the road becomes built-up as it runs through the village centre. A sharp right-left zigzag takes us into open country then we continue on to cross the wide River Tweed and then meet the B6356 coming in from the left.
We continue generally northeastwards across the fields, avoiding the summit of the hill to our left, on which Smailholm Tower is visible. After a few more bends we reach journey's end at a crossroads on the B6397; the road ahead is unclassified.