The B177 is a north-south road to the east of Ilford.
The road starts on the A124 Longbridge Road and heads north along the residential Goodmayes Lane into Goodmayes itself. The A1083 (former B176) is met at traffic lights and there is a short multiplex to the right to another set of lights where the B177 regains its northerly route.
It's not long before the road goes over the Great Eastern Main Line by Goodmayes station. On the far side the A118 Ilford High Road is met at traffic lights. This is the original northern end of the B177 on the original line of the A12. Now however the road continues ahead along Barley Lane through the suburbs. After passing the King George Hospital and Redbridge College the road ends on the edge of the urban area at traffic lights on the present A12 Eastern Avenue. The road was extended here after the Eastern Avenue opened (as the A106) in the mid-1920s.