The B790 is a short B-road in central Renfrewshire.
It starts at traffic lights on the B761 (former B788) in Bridge of Weir. The road heads east and soon leaves town. It passes to the north of a reservoir before continuing across the fields to Houston. Originally the road went through the village but now bypasses it to the south. The B789 comes in from the left and multiplexes along the B790 to a roundabout and the B790 then continues past - but not through - the houses to reach the far end of the bypass.
The road continues east across low-lying, flat land. It passes to the south of a wood, which formerly contained the Bishopton munitions works and is still owned by BAE Systems, hence the high fence around it. The road then runs along the River Gryfe for a short distance before going under the Inverclyde Line and the M8 at adjacent bridges. The road continues dead-straight for another few hundred yards before ending at a T-junction on the A726 on the edge of Brownsfield Industrial Estate.