[3] Runcorn was founded by Æthelflæd of Mercia in 915 AD as a fortification to guard against Viking invasion at a narrowing of the River Mersey.

[5] It remained a small, isolated settlement until the Industrial Revolution when the extension of the Bridgewater Canal to Runcorn in 1776 established it as a port which would link Liverpool with inland Manchester and Staffordshire.

In the late 18th and early 19th centuries, it was a spa and health resort but this ended with the growth of polluting industries, especially soap and chemical works.

Its location between Liverpool and Manchester and its links to the rail, motorway and canal networks have made it a centre for manufacturing, logistics, and wholesale and retail.

[9] The town's motto is Navem Mercibus Implere (Latin for "fill the ship with goods"), a classical quotation from Juvenal.

[10] 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".

[11] 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.

[12] The first recorded event in its history is the building by Æthelflæd of a fortification at Runcorn to protect the northern frontier of her kingdom of Mercia against the Vikings in 915.

[5] In 1536, the monastery was dissolved, and around nine years later, the buildings and some of the monastic lands were sold to Sir Richard Brooke who converted the habitable part of the abbey into a house.

[7] The growth of industry did not diminish Runcorn's late 18th and early 19th century reputation as a health resort and the "Montpelier of England".

[21][22] In the middle of the century, the growing wealth of the town and its industrialists saw the construction of several new landmarks, including Halton Grange, St Paul's Methodist Chapel and All Saints' Church.

[29] The ICI chemical plants at Runcorn featured in the Gestapo Black Book as a company of special interest but although the works at Weston Point were discussed at Luftwaffe briefings in 1940, the town was never deliberately targeted and was subject only to very limited bombing.

Runcorn was chosen because of its strong road, rail and canal connections, ample water supply, convenient location on the Mersey Estuary for the disposal of effluent, established industry and the availability of land for more.

It did, however, recommend that 500 acres (200 ha) around the village of Sutton Weaver to the south of the Chester–Manchester and Crewe–Liverpool railway lines be excluded from the designated area, partly to preserve its highly productive agricultural land.

[32] The new town masterplan of 1967 more than doubled the population as it encompassed neighbouring settlements and created new housing estates to the south and east.

The plan sought to increase public open space, reduce shopping provision, rationalise roads and renew housing stock.

[42] Runcorn is unparished with the exception of Sandymoor, and a large part of the Whitehouse Industrial Estate which falls under Preston Brook Parish Council.

[48] In April 2014, Halton Borough Council joined five other local authorities in Merseyside to form the Liverpool City Region.

To the east are the formerly separate villages of Halton and Norton, and the new town estates of Castlefields, Palacefields, Windmill Hill, Murdishaw, Brookvale, Hallwood Park, Beechwood and Sandymoor.

But since 2001, Inovyn (a wholly owned subsidiary of Ineos) has operated the extensive chemical works in the west of the town, employing 750 people in 2020.

It is home to the largest supercomputer in Europe and the Virtual Engineering Centre which works with Bentley motor cars, BAE Systems and Jaguar Land Rover.

[74] Runcorn's position between Liverpool and Manchester airports and its links to the rail, motorway and canal networks have made it a centre for logistics.

[82] Adjacent to it is Trident Retail Park containing shopping outlets and a cinema and nearby is a large Asda superstore that opened in 1989.

[34] Professor Arthur Ling, Runcorn Development Corporation's Master Planner, claimed to have invented the concept while sketching on the back of an envelope.

The home of a later industrialist, Thomas Johnson, became Runcorn Town Hall, a Grade II listed Italianate building with similarities to Osborne House on the Isle of Wight.

[105] The BBC situation comedy Two Pints of Lager and a Packet of Crisps was set in Runcorn and included external shots of the former Waterloo Hotel (known in the programme as The Archer), the Silver Jubilee Bridge and Halton Castle.

Norton Priory has been used as a location in historical dramas, sitcoms and children's programmes, including Little Birds, Bone Detectives (Channel 4), Island at War, Casanova and Young Dracula.

[111] The Runcorn Ferry is a monologue written by Marriott Edgar and popularised by Stanley Holloway celebrating the ancient river crossing which existed from the 12th century until the construction of the Transporter Bridge in 1905.

[122] The body responsible for planning health services in Runcorn, including primary care, is the Halton Clinical Commissioning Group.

Runcorn Ladies FC were established in January 2012, and played in the Liverpool Open Age Women's Division, finishing in an impressive 7th position in their very first season.