Bedfordshire Record Office's Guide to Bedfordshire Parishes describes Leighton-Linslade thus: Civil Parish created in 1965 from the parishes of Leighton Buzzard and Linslade [formerly Buckinghamshire]; includes Grovebury and Southcott
It consists of the settlements of Leighton Buzzard and Linslade, which have a single town council. The River Ouzel provides the border between the parts, with Leighton to the east and Linslade to the west. The two are served by Leighton Buzzard railway station, which is actually on the western side.
Leighton-Linslade Urban District was formed in 1965 by the merger of Leighton Buzzard Urban District, and Linslade Urban District (previously in Buckinghamshire). Under the Local Government Act 1972 the district was merged into South Bedfordshire in 1974, and was downgraded to a parish.
The parish participates in international town twinning: