The urban districts and rural districts of Northern Ireland had their origin in 1899, when the Local Government (Ireland) Act 1898 came into effect. They were based on the system of district councils introduced in England and Wales four years earlier. With the creation of Northern Ireland in 1921, it received six of Ireland's thirty-three administrative counties, each subdivided into a number of urban and rural districts, plus the county boroughs of Belfast and Derry which were administered outside the counties. In 1921 the number of rural districts was reduced by amalgamation.