The Great Western Railway (GWR) was established under the vision of Isambard Kingdom Brunel, to link London to North America on the quickest possible route, with steamships landing passengers and goods in West Wales as opposed to steaming to an English port.

Brunel, the GWR's Chief Engineer, originally proposed to situate the Welsh port at Fishguard, which was intended to be the terminus when the line was authorised in 1845.

But in 1852, under extensive shareholder pressure to deliver revenue, Brunel changed his mind in favour of Neyland, because it was sheltered and had deep water to allow large ships to dock.

[3] The western terminus of the SWR, a station originally named Milford Haven, was opened with the line on 15 April 1856.

[9] The Pembrokeshire Light Railway Society was launched in 1986 in an unsuccessful attempt to re-open the section of the line from Johnston to Neyland.