Wellingborough (ˈwɛlɪŋbərə ) is a market town and civil parish in the North Northamptonshire unitary authority area of Northamptonshire, England. It is from London and from Northampton, and is on the north side of the River Nene.
Originally named "Wendelingburgh" (the stronghold of Wændel's people), the Anglo-Saxon settlement is mentioned in the Domesday Book of 1086 as "Wendelburie". The town's market was granted a royal charter in 1201 by King John. At the 2021 census, it had a population of 56,564. The built-up area also includes suburbs Wilby, Great Doddington, Little Irchester, Redhill Grange, Stanton Cross and Glenvale Park.
The town was established in the Anglo-Saxon period and was called "Wendelingburgh". It is surrounded by five wells: Redwell, Hemmingwell, Witche's Well, Lady's Well and Whytewell, which appear on its coat of arms. Henrietta Maria came with her physician Théodore de Mayerne to take the waters on 14 July 1627.
The medieval town of Wellingborough housed a modest monastic grange – now the Jacobean Croyland Abbey – which was an offshoot of the monastery of Crowland (or Croyland) Abbey, near Peterborough, some down-river. This part of the town is known as Croyland.
All Hallows Church is the oldest existing building in Wellingborough and dates from c. 1160. The manor of Wellingborough belonged to Crowland Abbey Lincolnshire, from Saxon times and the monks probably built the original church. The earliest part of the building is the Norman doorway opening in from the later south porch. The church was enlarged with the addition of more side chapels and by the end of the 13th century had assumed more or less its present plan. The west tower, crowned with a graceful broach spire rising to , was completed about 1270, after which the chancel was rebuilt and given the east window twenty years later. The church was restored in 1861 by Edmund Francis Law. The 20th-century Church of St Mary was built by Ninian Comper.