Cardigan is an anglicisation of the Welsh Ceredigion ("Ceredig's land"), the surrounding territory its Norman castle once controlled.

The nearest known Roman forts were at Loventium and Bremia at the gold mines near Llanio above the River Teifi on the Sarn Helen road.

The present town grew up near the medieval forts established to control the access of the Teifi and its confluents to Cardigan Bay on the Irish Sea.

Its hinterland was regained by Owain Gwynedd, Cadwaladr ap Gruffydd, and Gruffydd ap Rhys in October 1136 after their victory at Crug Mawr over Norman forces army led by Roberts fitz Martin and fitz Stephen and Maurice FitzGerald.

[4][5] Welsh rule over Cardigan continued, for some periods under royal lordship, until it was annexed to the English crown in 1283 when the county of Cardiganshire was created.

The castle ceased being the administrative centre of the county with the Act of Union in 1536 and by the early 17th century was already falling into ruins.

In the 17th century, the residence erected around the old priory was famed as the home of Orinda (Catherine Philips), the friend of Jeremy Taylor.

[7] In the 18th and early 19th century, Cardigan was the commercial centre of its county[3] and the most important port in South Wales, exporting slate, oats, barley, and butter.

[8] It had a thriving shipbuilding industry, with over 200 vessels being built both in Cardigan and downstream in the village of Llandudoch (St Dogmaels).

[4] By mid-century, it was connected with the Welsh rail network but its harbour was obstructed by a sand bar that made it dangerous for vessels over 300 tons burden except during the high spring tides.

Information recorded in Trade Directories show that in 1830 there were Thirteen boot makers, three bakers, one miller, four blacksmiths, seven carpenters, two coopers, six tailors, five dressmakers and milliners, two straw hat makers, two weavers, three curriers, three saddlers, two whitesmiths, four glaziers, five maltsters, two printers, two tanners and one stonemason.

Cardigan Guildhall was built between 1858 and 1860 on the site of the old grammar school and a house with a coach-house owned by Abraham Morgan.

[6] The river silted up and larger vessels could no longer reach the port, which had largely become inactive by the early part of the 20th century.

[10] For the last 40 years of the 20th century, a factory in the town made 35,000 pairs of jeans per week for Marks & Spencer, but closed in 2002 with the loss of 400 jobs when M&S sourced from overseas.

A new jeans manufacturer—the Hiut Denim Company—opened in 2012, employing some of the original staff[11] and in 2017 became globally recognised for its connection with Meghan Markle.

[16][17] Cardigan lies astride the Afon Teifi and includes the last bridging point of the river before the sea 3 miles (5 km) northwest.

[20] Glaciolacustrine clay from local brick pits in Bath House Road and on the site of King George's field was used for brick-making until the early 20th century.

The nearest Met Office weather station for which online records are available is at Aberporth approximately 6 miles (9.7 km) east-northeast.

However, a group of volunteers and the local Catholic priest, Seamus Cunane, working separately, did raise its profile.

[5] In 1832, the Cardigan constituency was enlarged to include the Bridgend and Abbey hamlets of the parish of St Dogmaels on the south side of the River Teifi in Pembrokeshire.

Levi James, one of the town's two inaugural county councillors, was immediately made an alderman and became the second chairman of the council.

A public library was situated in 'Canolfan Teifi' near the guildhall, but, in July 2017 moved to the local Council Offices on Morgan Street.

[64] A blue plaque was put up at Cardigan Quay in 2018 to honour multiple powerboat champion, boat-builder and commentator Jonathan Jones in his home town.

Historically the farmers from the surrounding area would come to the town to hire workers and to inspect stallions that are put out to stud.

[68][69] The A487 coastal trunk road provides links to the northeast and southwest; the A478 south to Narberth and Tenby and the A484 southeast to Swansea.

Completion to Cardigan was slow; the opening was finally achieved on 1 September 1886 and on the same day the Great Western Railway took over the working of the line.

[70] The railway station closed to passengers prior to the Beeching Axe on 10 September 1962 but remained open to goods traffic until 27 May 1963.

After that, the station remained open as a coal depot until April 1965, staffed by British Railways staff until November 1964.

A local Welsh language newspaper uses the nickname of the line, Cardi bach,[72] as does the shuttle bus service between Cardigan and New Quay.

[73] The section of old trackbed between Cardigan and Cilgerran is now a footpath and cycle track to the Teifi estuary woodlands and marshes and the Welsh Wildlife Centre.