This article is about the current B109 in East Ham.
For the original B109 in Hackney, see B109 (Hackney)
The B109 is a short urban B-road in east London.
The road starts at traffic lights on the A118 Romford Road and heads south along the residential Katherine Road. Streets heading east-west here are more-or-less parallel whereas the B109 is not at all straight. It zigzags its way south to cross the B165 at traffic lights and then goes over a signposted weak bridge over the District Line. The road then straightens out and, still called Katherine Road, makes its way to its end at traffic lights on the A124 Barking Road.