| Elm Farm | |
| Owner: | Never built |
| Original: | Wimbledon and Sutton Railway |
| Locale: | St Helier |
| Coordinates: | 51.385°N -0.2001°W |
Elm Farm was an authorised railway station planned by the Wimbledon and Sutton Railway (W&SR) and Underground Electric Railways Company of London (UERL) but never built. It was to be located on the western edge of what is now St Helier on the border between the London Boroughs of Merton and Sutton, in south-west London.
The station was to have been built on the W&SR's planned surface railway line in Surrey (now south-west London) from Wimbledon to Sutton. The station was to be on the south side of Love Lane. The construction of the railway was approved in 1910. In 1911 the UERL agreed to provide funding for the line's construction and to operate its train services by extending the UERL's District Railway (DR) from Wimbledon station.
Delays in the purchase of land along the railway's route and the outbreak of war prevented the works from commencing and the permission was extended several times with a final extension granted in 1922. Following the war, the UERL presented new proposals to construct an extension of the City and South London Railway (C&SLR, now part of the Northern line) from Clapham Common to Morden in tunnel where it would come to the surface and join the W&SR route. Both DR and C&SLR trains would run to Sutton. The revised proposals omitted Elm Farm station from the W&SR route. The plan to extend the C&SLR was opposed by the Southern Railway (SR), the operator of the mainline services through Wimbledon and Sutton. A settlement between the companies agreed that the extension of the C&SLR would end at Morden and the W&SR would be taken over and its route would be constructed by the SR.
When the Wimbledon to Sutton line was constructed by the SR in the late 1920s, the nearest station to the proposed site of Elm Farm was St Helier to the north.