The district was made on April 1 , 1974 , under the Local Government Act 1972 , when the boroughs of Lancaster and Morecambe and Heysham , along with Carnforth urban district , Lancaster Rural District and Lunesdale Rural District joined together . The current city boundaries were set as part of the provisions of the Local Government Act 1972 , and cover an amalgamation of five former local government districtsâ '' the municipal boroughs of Lancaster and Morecambe and Heysham , together with the Carnforth Urban District and rural districts of Lancaster and Lunesdale , all from the administrative county of Lancashire .