Urban districts normally covered smaller towns, usually with populations of less than 30,000. Originally there had been 1,009 urban districts but implementation of the recommendations of a series of county reviews as established by the Local Government Act 1929 saw a net decrease of 159 in the number of urban districts between 1932 and 1938. In many instances smaller urban districts were merged with their surrounding rural districts, with the result that new districts emerged covering rural as well as urban parishes. At the same time, a number of larger urban districts became municipal boroughs (as already created, in 1835 under the Municipal Reform Act 1835): these had a slightly higher status and the right to appoint a mayor.