The B659 runs from Henlow Camp to Biggleswade in Bedfordshire. Until the 2000s it was part of the A6001.
The route starts at a roundabout on the A600 in Henlow Camp and heads roughly northeast. After leaving the RAF camp behind we cross open country and then cross the A507 just before reaching Henlow village. We run along the main street and then back into the fields. After passing a small wood the road bends sharply right to cross the River Ivel, then left to regain its northerly course and enter Langford.
The road runs along the lengthy High Street, which has very few side streets. On the far side of town an unclassified road, formerly the B658, bears left towards Broom and we then go under the A1 Biggleswade bypass and the road becomes urban once more. We enter town along Hitchen Street, then TOTSO left at traffic lights to avoid the narrow streets of the town centre. The road ends shortly afterwards at a mini-roundabout on the A6001 (former A1) at the western end of the High Street.
An OpenStreetMap trace for this route awaits uploading to the SABRE Wiki.