The B277 is a short B-road in the London Borough of Sutton.
The route starts opposite the church on the A232 Carshalton High Street, from where it heads north. Very distinctively for a suburban road, it first crosses a causeway over a lake before running between high brick walls which separate it from the grounds of an ecology centre on the left and extensive parkland (The Grove) to the right.
Soon, however, we reach a residential area and the route continues north, passing under a railway line to the east of Carshalton station. At a mini-roundabout – from where the unclassified Wrythe Green Road links westward to the B278, which has thus far paralleled our route one block to the west – the B277 turns to head northeast along Nightingale Road. After crossing the River Wandle at the Hack Bridge, and continuing for a short way along Hackbridge Road, the route ends at a junction with the A237 London Road.