Castle Street is a defunct electoral ward in Liverpool, in Merseyside, England, and part of the Liverpool Riverside parliamentary. Castle street was bordered to the north by the Exchange ward, to the south by the Port of Liverpool, the Lord Street and Church Street to the east and River Mersey to the west. Historically, it was part of Lancashire before the establishment of Merseyside.
Castle Street ward covered the area around Castle Street, one of Liverpool's original seven streets, in Liverpool's central business district. It connected Liverpool's town hall with the waterfront. It was primarily a commercial area, and had a commercial and business population.