An urban growth boundary, or UGB, is a regional boundary, set in an attempt to control urbanization by designating the area inside the boundary for high density urban development and the area outside the boundary for low density rural development.
An urban growth boundary circumscribes an entire metropolitan area and is used by local governments as a guide to zoning and land use decisions. If the area affected by the boundary includes multiple jurisdictions a special urban planning agency may be created by the state or regional government to manage the boundary. In a rural context, the terms town boundary, village curtilage or village envelope may be used to apply the same constraining principles.
Some jurisdictions refer to the area within an urban growth boundary as an urban growth area, or UGA. While the names are different, the concept is the same.
The US states of Oregon, Washington and Tennessee require cities to establish urban growth boundaries. Notable US cities which have adopted UGBs include Portland, Oregon, Minneapolis, Minnesota and various communities in the San Francisco Bay Area. Outside the US, a similar boundary exists in Vancouver, British Columbia, and boundaries to preserve greenspace and constrain the area of urban development existed in London as early as the 16th century. In the middle of the 20th century the countryside abutting the London conurbation was protected as the Metropolitan Green Belt.Places with urban growth boundaries
