The Liverpool Built-up Area is a term used by the Office for National Statistics (ONS) to denote the urban area around Liverpool in England, to the east of the River Mersey. The contiguous built-up area extends beyond the area administered by Liverpool City Council into adjoining local authority areas, particularly parts of Sefton and Knowsley. As defined by ONS, the area extends as far east as St Helens, Haydock, and Ashton-in-Makerfield in Greater Manchester.