Wahkiakum County On The March–Probably

In our feature on the rapid growth of Kittitas County you may have noticed the county that occupies the number two slot in the rate of net in-migration. To refresh your memory:

Yes, there is Wahkiakum County just behind Kittitas. Not sure where Wahkiakum County is? It is nestled between Cowlitz and Pacific counties along the Columbia River, with its county seat in Cathlamet, its only incorporated city. The most recent population estimates from the Office of Financial Management (OFM) for Wahkiakum County give it 4,210 souls, making it the third smallest county in the state.

According to those same estimates, parents in Wahkiakum County welcomed 22 new children into the world between April 2019 and April 2020. Meanwhile, the county had the highest death rate in the state, and 73 Wahkiakomians shuffled off their mortal coils that year. Down 51 residents on the natural side, the state estimates that 71 more people moved into Wahkiakum county than left, for a net increase of 20 people on the year.

All this sounds great, but it does illustrate the problem of making population estimates when the numbers are very small. 20 people might be just a few households, and no one goes around counting noses between the decennial census, so missing a few families coming and going makes a big difference in population estimates. Because birth and death data is quite accurate (everyone gets a government certificate for both) all the error in population estimating falls on the net migration figure.

As a rule, the smaller the area, the harder it is to estimate population using the sorts of quantitative modeling techniques that the OFM employs. A small change in a small area can make a big difference. The arrival or departure of a single employer can shift population quite a bit, as people move in or out in search of opportunity.

Now, to be fair to OFM here, the migration estimates published by the Internal Revenue Service, which track address changes on tax forms, do show that between 2017 and 2018 (most recent data) 276 people moved into Wahkiakum County and 186 people moved out, for a net gain of 90 new Wahkiakomians that year. And the figures in the chart above are for a three-year average. So it is a good bet that Wahkiakum County is seeing a steady influx of new residents.

The point, though, is that in very small counties like Wahkiakum, crunching data is not enough to understand population dynamics. Small areas need what demographers refer to as “structural” analysis, or the exploration of changes taking place on the ground.

Next time you’re driving to Portland, take a detour west on Route 4 at Kelso, head to Cathlamet, cross Puget Island, take the Cathlamet-Westport Ferry across the Columbia and head down U.S. Route 30 to Portland. You too may fall in love with Wahkiakum County.