It wasn’t long after the pandemic hit that we began to hear predictions of a mass exodus from dense urban centers for suburbs and smaller cities and towns. It’s still a matter of conjecture.

But new data shows that even at the height of the Seattle boom, plenty of folks were already heading out of King County.

Data released last week by the U.S. Census Bureau tracks county-to-county movement across the U.S. between 2014 and 2018, a period during which Seattle was growing faster than any other major city. And it shows that King County was shedding people to the rest of Washington during these boom years.

Each year, about 62,800 people moved from King County to another county in Washington. When compared with the period just before the Seattle boom, in 2009-2013, that’s a 43% increase.

Folks moving in the reverse direction — from another part of Washington into King County — averaged just 41,100 per year. That’s a tiny 4% increase from the 2009-2013 period.

The bulk of the movers away from King went to nearby counties. Snohomish absorbed the most, at about 21,000 per year in this period, slightly ahead of Pierce County. Kitsap ranks third at 2,900 per year.


It’s likely that many of these folks left King County due to the high cost of housing. And it’s probably for that same reason that movers into King County from other parts of Washington barely grew in this period.

Clearly, it wasn’t Washingtonians who were fueling King County’s rapid growth during this period. Rather, people from much farther afield were behind it.

With our strong economy and desirable (for many) lifestyle, the Seattle area was a magnet for people from other parts of the country and the world in this period.

About 80,600 people moved into King County from other states each year, on average, from 2014-2018. That’s a lot more than the 59,600 who moved in the reverse direction, from King to another state.

The biggest exporter of people to King County was, unsurprisingly, California, averaging about 18,000 per year. Oregon was a distant second at 5,800, a little more than No. 3 Arizona.

While we famously complain about the hordes of Californians who move here every year, we send plenty folks their way too. Among those who moved away from King County, California was by far the biggest draw (not including the rest of Washington), averaging 13,800 per year in the 2014-2018 period. Oregon ranks second at 4,300 per year, followed closely by Arizona.


If you add all the people who moved into King County each year from some other part of Washington or the U.S. during this period, it totals about 121,500. And the number who left King for another county in Washington or some other state pencils out to around 122,400.

Basically, it was a wash.

So how did King County grow during this boom period?


The data shows King County added about 34,600 people each year who moved here from another country. More than half of the people who moved here from abroad came from a country in Asia. Europe ranks second, followed by Central America. (The data does not capture people who moved from King County to a foreign country, but that is certainly a much smaller number).

When compared with the period just before the Seattle boom (2009-2013), the biggest growth was among these movers from abroad — an increase of nearly 50%. A lot of that growth, of course, was fueled by tech industry employment of workers from Asian countries.

Which counties does King lose the most people to, taking into account that the flow goes in both directions?

Of the 10 counties with which King has the greatest net losses, eight are in Washington. We have the greatest deficit by far to Snohomish and Pierce, as expected. Perhaps more surprising, Whatcom ranks 3rd. This is most likely because of the large number of college students moving from King County to go to Western Washington University in Bellingham.

The two non-Washington counties in the top 10 for net losses couldn’t be much more different from each other: New York County — also known as Manhattan — and Salt Lake County in Utah.


Of the 10 counties from which we had greatest net gains, nine were out-of-state. The greatest surplus was with Los Angeles, one of three California counties on the list. No. 2 is Cook County, Illinois (Chicago), followed by Harris County, Texas (Houston).

The sole Washington county on the list surprised me — Cowlitz, which is in the southwestern part of the state.

Hardly anyone from King County relocated to Cowlitz (only about 50 people annually), but roughly 800 folks per year moved in the opposite direction.


Correction: An earlier version of this column misstated the number of people who moved each year into King County from another county in Washington. The correct number is 41,100.