Under the and 1875 the Poor Law Unions were used as the basis for sanitary districts. All municipal boroughs and areas with bodies such as improvement commissioners became Urban Sanitary Districts. (Any area which acquired borough or urban status after the Act also became at that point an Urban Sanitary District). The remaining areas of the country - i.e., the Unions minus the urban areas - became Rural Sanitary Districts. Under the Local Government Act 1894 the Urban and Rural Sanitary Districts in Dorset were succeeded by Urban Districts and Rural Districts.