The Chester and Holyhead Railway was an early railway company conceived to improve transmission of Government dispatches between London and Ireland, as well as ordinary railway objectives. Its construction was hugely expensive, chiefly due to the cost of building the Britannia Tubular Bridge over the Menai Strait. The company had relied on Government support in facilitating the ferry service, and this proved to be uncertain. The company opened its main line throughout in 1850. It relied on the co-operation of other railways to reach London, and in 1859 it was absorbed by the London and North Western Railway.
There were extensive mineral deposits at a number of locations south of the C&HR main line, and the C&HR and the LNWR encouraged the building of branch lines to serve them. Llandudno was an early centre of leisure and holiday travel, and in the last decades of the nineteenth century, that traffic became increasingly important. In the twentieth century, the North Wales coast became a popular holiday destination, reached largely by rail travel.
In 1970, the Britannia Tubular Bridge suffered a serious fire, and the line was closed at that point until 1972 when a new structure at the same site was brought into use.
The container traffic at Holyhead has ceased, and passenger connections to the Irish ferries are much reduced, but the entire original main line is still in use for passenger traffic, together with the Llandudno branch and the Conwy Valley line to Blaenau Ffestiniog.