Note: During the 19th and 20th centuries the town of Saint Albans and the surrounding district grew as part of the suburban expansion of London. The district became part of the so-called Green Belt surrounding London. Development has been limited since the mid-20th century. In addition to the town of Saint Albans, the district includes rural areas and the town of Harpenden. The district has an area of 62 square miles (161 square km). The district's population, as of a 1998 estimate, is 131,400. The district of Saint Albans is sometimes referred to as the "city and district" of Saint Albans; there is a district council.