Sham Shui Po is located in the northwestern part of the Kowloon Peninsula, covering an area of about 1,047 hectares with a population of about 353,000, and is divided into 21 constituencies. The district is bounded on the north by the Lion Rock Country Park in Sha Tin, on the east by the Kowloon-Canton Railway (i.e. the MTR East Rail Line), on the south by Boundary Street, and on the west by the waterfront, including Stonecutters Island. It is one of the earliest development areas of Hong Kong, and was once an industrial, commercial and transportation hub. Sham Shui Po District is one of the earliest development areas in Hong Kong, China, and was once an industrial, commercial and transportation hub. Much of the land in the district has been used for residential development, such as public housing estates covering nearly 81 hectares, while Cheung Sha Wan still has many factories and warehouses. In addition, the People's Liberation Army (PLA) Barracks on Stonecutters Island is also part of the district. The district was already densely populated in the 1950s and 1960s, with a population of 440,000 in 1986, but the population has dropped to 353,000 since then. It is the poorest district with the lowest median monthly household income ($14,000). It has the highest proportion of elderly people (15.7%) and a high proportion of new arrivals (11.2%). The district is about equally divided between public and private housing, with 13 public housing estates (including Shek Kip Mei Estate, the earliest public housing estate in Hong Kong) and seven Home Ownership Scheme estates. Owing to the lack of town planning in the early years, the cityscape has become chaotic, and most of the buildings were built in the 1950s and 1960s and are very dilapidated, with unauthorized building works (UBWs) found everywhere, giving rise to a lot of building management and fire prevention problems. The largest number of such buildings is found in Nam Cheong Sub-district (around Fuk Wing Street, Fuk Wah Street and Pei Ho Street). The district is well connected by the MTR, the Airport Express and the superhighway network, making it easy to travel to and from the district and other districts in Hong Kong, Kowloon and the New Territories. There are two hospitals, one university (City University of Hong Kong), 80 schools, three community halls (Lai Kok, Pak Tin and Shek Kip Mei) and four community centers (Cheung Sha Wan, Tai Hang Tung, Nam Cheong and Lai Chi Kok) in the district.