Zoning is the process of dividing land in a municipality into zones (e.g. residential, industrial) in which certain land uses are permitted or prohibited. The type of zone determines whether planning permission for a given development is granted. Zoning may specify a variety of outright and conditional uses of land. It may also indicate the size and dimensions of land area as well as the form and scale of buildings. These guidelines are set in order to guide urban growth and development.
Around the turn of the 20th century, a rapid urbanization process and influx of immigrants transformed the country. Middle and upper-classes consequently encountered much greater diversity than they had before making the intrusion of unwanted people into their neighborhoods appear more conceivable. As a result, many cities began implementing the first exclusionary zoning policies. In 1908, Los Angeles adopted the first citywide zoning ordinance protecting residential areas from the entrance of these undesirable community elements. Many of these early regulations directly darred racial and ethnic minorities from community residence, until explicit racial zoning was declared unconstitutional in 1917.
The United States federal government finally addressed the issue with the enactment of the Standard State Zoning Enabling Act of 1922. This legislation established a model framework for zoning ordinances, which states could adopt or adapt to delegate land-use power to local authorities for the protection of "public safety, health, morals and welfare."
The Supreme Court considered zoning's constitutionality in the 1926 landmark case of Village of Euclid, Ohio v. Ambler Realty Co.. The court ultimately condoned zoning as an acceptable means of community regulation. Following this verdict, the number of municipalities with zoning legislation multiplied from 368 in 1925 to over 1,000 in 1930.