Incorporated on 10th August 1857.
A 54 mile line between Castle Douglas and Portpatrick. Subscribed to by the Lancaster and Carlisle (£100,000), the Glasgow and South Western (£100,000), and the Belfast and County Down (£15,000) companies. It opened in 1861 and amalgamated with the Wigtownshire Railway to form the Portpatrick and Wigtownshire Joint Railway in 1885, later taken over by the London and North Western, the Midland, the Caledonian, and the Glasgow and South Western Railways jointly.
Capital £460,000 in £10 shares, loans of £150,000.