Three Bridges railway station is located in and named after the village of Three Bridges, which is now a district of Crawley, West Sussex, England. It is at the point where the Arun Valley Line diverges from the Brighton Main Line and Thameslink, 29 miles 21 chains (47.1 km) down the line from London Bridge via Redhill.

The Arun Valley line, also known as the Mid Sussex line, is part of the Southern- and Thameslink-operated railway services. For the initial part of the route trains follow the Brighton Main Line, and at a junction south of Three Bridges the route turns westwards. It then runs via Crawley, Horsham and Arundel, before meeting the West Coastway line at Arundel Junction. Trains on the Arun Valley line then proceed to either Bognor Regis, Portsmouth & Southsea or Southampton Central.