The regions of Singapore serve as urban planning subdivisions of the country at the highest level as demarcated by the Urban Redevelopment Authority (URA) to support its planning work. Over time, other government agencies have also adopted these five regions for administrative purposes, such as the Department of Statistics in conducting censuses. Singapore's regions are further subdivided into 55 planning areas on the second level, which include two water catchment areas, and planning areas are further divided into subzones on the lowest level. The largest region in terms of area is the West Region with 218.4 km (84.3 sq mi), while the Central Region is the most populous with an estimated population of 922,980 inhabitants in the area in 2019.
The country is governed as a unitary state without provinces or states. While referenced by some government organisations, these regions are not formal administrative subdivisions but are mainly geographical in nature or used for urban planning. For local governance, Singapore is divided into five Community Development Council (CDC) districts on the second level, each headed by a mayor. These districts are made up of electoral constituencies, which are administered at the lowest level by town councils. A town council may oversee one or more constituencies, and its boundaries do not necessarily align with those of CDC districts. CDC mayors are not directly elected but are Members of Parliament (MPs) representing constituencies within their respective districts. Electoral boundaries can change with each general election, while regional and planning area boundaries have remained largely fixed.