Administrative districts, created in 1875, expanding on the role previously held by the Poor Law Unions. Rural sanitary districts were formed in all areas without a town government. Rural Sanitary Districts followed the boundaries of existing Poor Law Unions, less any of those areas within Urban Sanitary Districts. Any subsequent change in the area of the Poor Law Union also changed the area of the sanitary district. Sanitary Districts were superceded by Urban Districts and Rural Districts in 1894. Holsworthy and Tavistock Rural Sanitary Districts were primarily in the county of Devon, but included parts within Cornwall.