The nearest settlement recorded in the Domesday Book was Wibalditone, with 21 inhabitants and a church, whose name possibly survives in Willington's Farm on the edge of Didcot's present-day Ladygrove Estate.

[13] The oldest surviving house in Didcot is White Cottage, a 16th-century timber-framed building in Manor Road that has a wood shingle roof.

[14] At that time the village centre consisted of a group of cottages and surrounding farms around Manor, Foxhall and Lydalls Roads.

Although longer, a cheaper-to-build line to Bristol would have been through Abingdon farther north but the landowner, the first Lord Wantage, is reputed to have prevented that alignment.

Didcot's junction of the routes to London, Bristol, Oxford and to Southampton via the Didcot, Newbury and Southampton Railway (DN&S) made the town militarily important, especially during the First World War campaign on the Western Front and the Second World War preparations for D-Day.

The DN&S line has since closed, and the large Army and Royal Air Force ordnance depots have disappeared beneath the power station and Milton Park Business Park; however the 11 Explosive Ordnance Disposal and Search Regiment RLC is still based at the Vauxhall Barracks in the town.

This line, designed to provide a direct link to the south coast from the Midlands and the North avoiding the indirect and congested route via Reading and Basingstoke, was built in 1879–82 after previous proposals had failed.

It was designed as a main line and was engineered by John Fowler and built by contractors TH Falkiner and Sir Thomas Tancred, who together also constructed the Forth Railway Bridge.

[16] It was a very costly line to build due to the heavy engineering challenges of crossing the Berkshire and Hampshire Downs with a 1 in 106 gradient to allow for higher mainline speeds, and this initial cost and the initially lower than expected traffic volumes caused the company financial problems.

[19] As part of the Science Vale Enterprise Zone, Didcot is surrounded by one of the largest scientific clusters in the United Kingdom.

[20] The Diamond Light Source synchrotron, based at the Harwell Campus, is the largest UK-funded scientific facility to be built for more than 30 years.

[21] Didcot has been designated as one of the three major growth areas in Oxfordshire; the Ladygrove development, to the north and east of the railway line on the former marshland, is set to double the number of homes in the town since construction began in the late 1980s.

Designed by Ellis William Architects, the centre is clad with silvered aluminium panels and has a window wall, used to connect the building with passing shoppers.

[26] The Railway Centre is often used as period film set and has featured in works including Anna Karenina, Sherlock Holmes: A Game of Shadows and The Elephant Man.

The station was originally called Didcot but then renamed Didcot Parkway in 1985 by British Rail; the site of the old GWR provender stores, which had been demolished in 1976 (the provender pond was kept to maintain the water table) was made into a large car park to attract passengers from the surrounding area.

[citation needed] In October 2010, Didcot Sewage Works became the first in the UK to produce biomethane gas supplied to the National Grid, for use in up to 200 homes in Oxfordshire.

[30] On Sunday 27 July 2014 three of the six 114-metre (374 ft) cooling towers were demolished in the early hours of the morning, using 180 kilograms (400 lb) of explosives.

[31] On Tuesday 23 February 2016, part of the boiler house building at the power station collapsed; one person was declared dead, five injured and three missing.

[42] More recently, Didcot is home to a Pirelli distribution and logistics centre which provides tyres for Formula One Grand Prix motor racing events across Europe.

[43][44] In 2015 the head offices of the Bloodhound SSC Land Speed Record attempt team were moved to the new University Technical College (UTC) Oxfordshire site on the boundary between Didcot and Harwell.

[45] Didcot is surrounded by farmland which has historically grown traditional British crops such as wheat and barley, sheep farming is also common in the area.

[46] The area is also noted for farmers growing opium poppies for legal production of morphine and heroin to meet National Health Service demand.

[47] The poppies produced are sold to Macfarlan Smith, a major pharmaceutical company, who hold a licence from the United Kingdom's Home Office.

[53] The district in England with the highest healthy life expectancy, according to an Office for National Statistics (ONS) study, is the 1990s-built Ladygrove Estate in Didcot.

[58][59] Didcot is served by seven primary schools: All Saints' C of E, Aureus, Ladygrove Park, Manor, Northbourne C of E, Stephen Freeman and Willowcroft.

[64][65] Didcot Choral Society, founded in 1958, performs three concerts a year in various venues around the town as well as an annual tour (Paris in 2008, Belgium in 2009).

The OVO Energy Women's Tour, a road cycling event, passed through Didcot on 12 June 2019.

[83] Didcot Town Football Club's home ground is the Loop Meadow Stadium on the Ladygrove Estate, having moved from their previous pitch off Station Road in 1999 to make way for the new Orchard Centre development.

[86] Didcot's synonymous connection with railways was noted in Douglas Adams and John Lloyd's humorous book the Meaning of Liff, published in 1983.

[100] In March 2018, anonymous artist Athirty4 added a series of fictional fantasy names to a number of road signs in Didcot.