Runcorn railway station is on a branch of the West Coast Main Line and provides frequent services to the Liverpool Lime Street, Birmingham New Street, and London Euston stations. The A533 road passes through the town from the south, crossing the Runcorn Gap over the Silver Jubilee Bridge, the lowest bridge crossing of the River Mersey. The Manchester Ship Canal runs alongside the Runcorn bank of the River Mersey; the Bridgewater Canal terminates in the canal basin in the town centre, as the staircase of locks leading down to the ship canal was filled in many decades ago.
Runcorn was a small, isolated village until the Industrial Revolution. It was a health resort in the late 18th and early 19th centuries. Towards the end of the 18th century, a port began to develop on the south bank of the River Mersey. During the 19th century, industries developed the manufacture of soap and alkali, quarrying, shipbuilding, engineering, and tanning. In the early 20th century, the prime industries were chemicals and tanning. The original village has grown to include what were outlying villages.
Except for chemicals, all of the old industries have disappeared and there has been diversification, in particular because of the close links to the motorway system and the development of warehousing and distribution centres. A new town was built to the east of the existing town in the 1960s and 1970s, and areas of private housing have been established farther to the east; this has resulted in the population more than doubling from around 26,000 to its present level of 70,000.
The earliest written reference to the town is in the Anglo-Saxon Chronicle, where it is spelled "Rumcofan", literally meaning "a wide cove or bay". This word is derived from the Old English words "rúm" ("wide" or "broad") and "cofa" ("cave" or "cove"). Other historical spellings of Runcorn include "Rumcoven", "Ronchestorn", "Runckhorne", and "Runcorne".
Little is known about the early history of the settlement but isolated findings of objects from the Stone, Bronze, and Iron Ages have been made and there is evidence of a Roman presence in the area. The earliest recorded event in its history is the building by Ethelfleda of a fortification at Runcorn to protect the northern frontier of her kingdom of Mercia against the Vikings in 915. The fort was built on Castle Rock overlooking the River Mersey at Runcorn Gap.