This dataset contains census, election, and vital statistics data for 118 British and Irish counties for the period 1851 to 1966. The information was collected for use in a study of regional integration and development in Great Britain in the 19th and 20th centuries. Included are population indicators for each of the counties recorded at 11 points in time during the 115-year span (i.e., 1851, 1861, 1871, 1881, 1891, 1901, 1911, 1921, 1931, 1951, and 1961).