What is “local”?
Local means sourcing close by. But what does that mean exactly? What is a reasonable distance to consider local?
Definitions of “local” vary widely. The US government defines “local” as within 400 miles of a location. In our case, this is Portland, Oregon. Given that no reasoning was offered as to why the number 400 was chosen, I’m going a bit further and defining the term according to transportation infrastructure, in particular roads.
In the US, the vast majority of food reaches its destination by truck (some 70%), so trucking distances are a good way to measure. Although 11 hours is the maximum shift allowed for truck drivers, I’m going to be a bit more conservative and use the standard 8 hour shift to give us some leeway.
480 mile radius from Portland.
So, driving at 60 miles an hour, a truck should be able to reach up to 480 miles over an eight-hour shift. Using simple radius, we can get a general idea of how far our local region extends.
Local region
Now, a radius is a useful tool to get a general sense of distance, but real-world limitations such as geography (mountain ranges, rivers, borders, etc.) and road networks have an impact on the actual distances that can be reached in 8 hours.
Taking these into account, we are left with the counties in the map above: these counties make up our local region.
Map of Portland’s local region.
Local zones
Now, even though all of these counties can be considered a part of our local region, there's still enough of a difference between many of the most distant counties and our closest areas. These counties combined make up an area about the size of Spain or France.
In real terms, there’s still a big difference between produce brought in from a farm in Multnomah County and produce trucked in from Chico, California. I think it’s therefore necessary to make additional distinctions.
I suggest breaking our local region into three zones, again based on trucking patterns:
Local
A 120 mile radius, or 2 hours of travel. This area only requires local trucking. Zone 1 contains the Portland Metro, and most of the Willamette Valley and the Central Coast.
Local Import
240 mile radius, or 4 hours of travel. Regional short-haul trucking may be required, but can generally be completed in a day.
Regional Import
A 480 mile radius, or up to 8 hours of travel. Regional short-haul is necessary, and may require an overnight trip. This is the furthest reasonable distance to include in the “local region” around Portland.
Map of Portland’s local zones.
