Waterloo is an area of the Metropolitan Borough of Sefton, in Merseyside, England. Along with Seaforth the two localities make up the Sefton Ward of Church. The area is bordered by Crosby to the north, Seaforth to the south, the Rimrose Valley country park to the east, and to the west the Crosby Beach and Crosby Coastal Park.

The Metropolitan Borough of Sefton is a metropolitan borough of Merseyside, England. It was formed on 1 April 1974, by the amalgamation of the county boroughs of Bootle and Southport, the municipal borough of Crosby, the urban districts of Formby and Litherland, and part of West Lancashire Rural District. It consists of a coastal strip of land on the Irish Sea which extends from Southport in the north to Bootle in the south, and an inland part to Maghull in the south-east, bounded by the city of Liverpool to the south, the Metropolitan Borough of Knowsley to the south-east, and West Lancashire to the east.