The settlements of Connah's Quay, Shotton and Queensferry, together with Deeside Industrial Estate, lie on the River Dee estuary and the whole area is commonly known as Deeside.
Connah's Quay (Cei Connah in Welsh) is the largest town in Flintshire and the derivation of its name is subject to different interpretations. One view is that it came from the name of the landlord of The Old Quay House by the docks, another is that Connah was the owner of a chandlery store on the docks. A further version is that Mary Connah owned the docks and when people crossed the Dee they asked to be taken to Connah's Quay. The name was in common usage from the 1860s and town acted as a small port with a shipyard. The dock was served by the Wrexham, Mold and Connah's Quay Railway which transported pottery from Buckley. The current town includes the former hamlets of Wepre, Golftyn and Kelsterton. Deeside College was formerly known as Kelsterton College and provides further education for the area, along with the sixth form at Connah's Quay High School. Wepre Woods is an area of ancient woodland within the town and this public area also includes the ruins of Ewloe Castle. The population of Connah's Quay at the 2001 census was 16,526.
Shotton is an Anglo-Saxon name meaning farmstead in the glade and it remained a cluster of hamlets until the nineteenth century. Shotton, Nine Houses and Shotton Hall (dating from 1637) made up this small settlement until the industrialisation of the area. Coal mining became important from the eighteenth century and the Hawarden Railway Bridge over the River Dee was opened in 1889, which improved access to the reclaimed Dee Marshes. As a result, John Summers and Son from Stalybridge established their steelworks at Shotton in 1896, which employed 250 men. This provided the catalyst for development and housing was built to accommodate the increasing number of workers needed for the ironworks. It also became a railway junction and in the early twentieth century there were also two brickmaking companies. The steelworks were nationalised in the twentieth century to form part of British Steel, but are now privately owned by the Corus Group. Shotton has a current population of around 9,000 people
In 1917 a private flying school was established by Tom Dutton on fields owned by the John Summers steelworks. The Royal Flying Corps took it over in the following year in order to train pilots and Dutton became one of the trainers. In 1918 the RFC became the RAF and the base was known as RAF Shotwick. RAF Sealand (as it later became) was used to train pilots for the Second World War but was never a fighter plane base. After the war it acted a maintenance unit for aircraft and equipment. Between 1951 and 1967 it was a US Air Force base and it eventually closed in 1996, although a Defence Avionics Repair Agency still uses the site.
Queensferry (y Fferi Isaf in Welsh) lies on the River Dee near the English border. The settlement is not strictly considered to be a part of Deeside, but Deeside appears in the name of many of Queensferry's features, including the Deeside Leisure Centre which is a large sports and leisure venue.
Deeside Industrial Park is a significant industrial area which has attracted a range of companies including the Toyota car manufacturing plant, two paper mills and two gas-fired power stations. The Flintshire Bridge was built between 1994 and 1997, at a cost of £55 million, and now provides a crossing point of the Dee between Shotton and Connah's Quay.