Most of the Urban Growth Boundary Maps in this collection were created in 1978, but some updated versions are included. Dates range from 1978 to 1995. Every six years, Metro prepares a forecast of population and employment growth for the region for the next 20 years and, if necessary, adjusts the boundary to meet the needs of growth forecast for that 20-year period.
Oregon Governor Tom McCall (1967-1975) convinced the Oregon Legislature in 1973 to adopt the nation's first set of statewide land use planning laws. With a coalition of farmers and environmentalists, McCall persuaded the Legislature that the state's natural beauty and easy access to nature would be lost in a rising tide of urban sprawl. On May 29, 1973, Senate Bill (SB) 100 was signed into law by Gov. McCall. The bill created the Land Conservation and Development Commission and the Department of Land Conservation and Development.
To meet SB 100’s requirements, the Columbia Region Association of Governments, Metro's predecessor, proposed an urban growth boundary for the Portland region in 1977. The plans and growth projections of Clackamas, Multnomah and Washington counties, along with 24 cities and more than 60 special service districts, had to be accommodated when drawing the initial boundary.
When Metro was created by voters in 1978, it inherited the boundary planning effort. That year, the Oregon Legislature gave Metro responsibility for managing the Portland metropolitan area’s urban growth boundary. Since 1997, Oregon law also requires Metro to maintain a 20-year supply of land for future residential development inside the boundary.
Oregon’s urban growth boundaries are not intended to be static. Since the late 1970s, the Portland metropolitan area boundary has been expanded about three dozen times. Most moves were small – 20 acres or less.
For more see Metro’s website: Urban Growth Boundary