It's part of the fabric of the Portland region, a line in the soil that separates city from country – a line that isn't crossed without careful consideration.
The region's urban growth boundary, set by the Metro Council, is up for review this year. The council is obligated to make sure there's enough room within the UGB to accommodate 20 years of growth, even if the boundary didn't budge in that timeframe.
Seems straightforward, right? Not quite. People can disagree on numbers and statistics, and politics will play a role as well. The Metro Council has to balance the needs of developers, mayors, land conservation advocates, city and suburban dwellers, and rural residents trying to keep the city away from their farms and forests.
Here is a look at some of the issues that will come into play as the region examines its edge.
Apartments under construction on Division Street in Southeast Portland in 2014.
Density
The region is required to have enough land for 20 years worth of growth. But if most of those new residents end up in new apartments in inner Portland and other community hubs, the region needs to add less land for single-family homes on the UGB edge. Areas like North Interstate and North Williams avenues and Southeast Division Street are all seeing more housing, which could end up saving farm and forestland.
Spillover
Setting the urban growth boundary isn't just about preserving the farms and forests nearest Portland. If the Metro Council goes too low on its growth projections, consequences could be far-reaching – consumers could decide to live in Clark, Columbia or Yamhill counties instead, creating new strains on the region's infrastructure.
Growth
Metro's economists will give the Metro Council what's called a range forecast – a look at what might happen if the Portland region grows quickly, grows slowly or somewhere in between. It's based on birth rates, economic growth and other factors. It's up to the Metro Council to decide how much growth to expect, and which forecast to plan for.
Damascus
More than a decade ago, the Metro Council brought the Damascus area into the UGB, thinking it would play a big role in accommodating 20 years worth of growth. But that community has struggled with deciding what its future character should be, and development is stalled until those questions are answered. Metro has to factor in that uncertainty when deciding how much growth Damascus can support during the next 20 years.
Voter-approved annexation
In some places, the Metro Council doesn't make the only call on whether an area grows. Oregon City and Sherwood are the only cities in our region where the voters have to approve any expansion of the city limits. Without that approval, no new development will happen.
Industrial land
Metro is responsible for ensuring there's enough room for 20 years of growth – not only for residents, but for jobs as well. Expect discussion about how to convert brownfields already within the urban growth boundary into industrial jobs, and whether to make new sites available beyond the UGB.
Westside resolution
One of the key political battlegrounds for the UGB historically has been western Washington County – but not this time. A move by the Oregon Legislature to shore up the region's 50-year growth plan also added hundreds of acres of land to the UGB near Hillsboro, Cornelius and Forest Grove. The bill also defined how those cities can grow beyond this expansion.