The A124 road is a road in east London linking Canning Town with Upminster.
The road begins at a junction with the A13 road (51.5157°N 0.0081°E / 51.5157; 0.0081 (A124 road (western end))) at Canning Town station in the south west of the London Borough of Newham. The road continues in a north easterly direction for 3 miles (4.9 km) as Barking Road, passing through West Ham, Plaistow and East Ham.
The road passes into the London Borough of Barking and Dagenham at a crossing of the River Roding and there forms a junction with the North Circular Road. The road bypasses Barking town centre as the Northern Relief Road and is then called Longbridge Road for 2 miles (3.2 km), forming a short section of dual carriageway and part of the borough boundary with the London Borough of Redbridge.
The road becomes Wood Lane at Becontree and continues north easterly for 1.9 miles (3.1 km) as far as Becontree Heath, where it passes into the London Borough of Havering and becomes Rush Green Road from there to Roneo Corner, a distance of 1.2 miles (2 km). The road then becomes Hornchurch Road and passes through Hornchurch, where it forms the High Street. After Hornchurch the road becomes Upminster Road and continues past Upminster Bridge tube station, becoming St Mary's Lane at the River Ingrebourne, and ends at Bell Corner in Upminster (51.5562°N 0.2491°E / 51.5562; 0.2491 (A124 road (eastern end))).
The road is served by London Buses route 5 from Canning Town to Roneo Corner and by London Buses route 248 from there to Upminster; with other routes also serving various sections.
The A124 Barking Road formed part of the original A13 route between Canning Town and Barking, prior to the opening of the East Ham & Barking Bypass in 1928, although the latter was briefly designated A118. The original eastern terminus of the A124 was Roneo Corner.