CogKnoSys

Knowledge you can walk. Read the idea below, then step up to the general, across to peers or down to the specific.

Physical

Clark County, Washington

Clark County is the southernmost county in Washington, across the Columbia River from Portland, with Vancouver as its county seat.

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↓ Specific: nothing more specific yet

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The idea

Clark County is the southernmost county in the U.S. state of Washington. It lies across the Columbia River from Portland, Oregon, and it is part of the Portland metropolitan area. Its county seat is Vancouver. A county seat is the town where a county's government has its main offices, such as its courthouse.

The Columbia River wraps around the county on two sides, and the North Fork of the Lewis River forms its northern edge. The flat land in the center and southwest of the county was carved by huge floods from the prehistoric Lake Missoula. These Missoula Floods were set loose thousands of years ago, as several ice dams melted.

Clark County was the first county in Washington. It was created by the Provisional Government of Oregon while the land was still part of Oregon Country, and at first it covered the entire present-day state. Its name honors William Clark of the Lewis and Clark Expedition. Since it once covered the whole future state, every other county in Washington was later formed from land that had started out as part of it.

Some residents cross the Columbia River to shop in Oregon, which has no sales tax. In 2019, about 65,000 Clark County residents commuted to work in Portland.

Check yourself

Question 1 of 3

Which river forms the northern edge of Clark County?

Pick one. The first pick counts.

Composition

what it's made of

  • Vancouver — The county seat, on the Columbia River.
  • Columbia River border — The river separates the county from Portland, Oregon.
  • Cascade foothills — Forested foothills in the east and north, rising to 4,000 feet.
  • Founding history — Created as Vancouver District in August 1845, renamed Vancouver County that December, and renamed for William Clark in 1849.

Connection

how it relates

Under Lower Columbia Counties

In place

  1. Vancouver, Washingtonstrength 90 of 100

    Vancouver is the county seat of Clark County.

  2. Portland, Oregonstrength 70 of 100

    Clark County lies across the Columbia River from Portland, Oregon.

  3. Columbia Riverstrength 70 of 100

    The Columbia River separates Clark County from Portland, Oregon.

Change

how and why it evolves

Past
The county was first created on August 20, 1845, as Vancouver District, and that December it was renamed Vancouver County. In 1849 the Oregon Territorial Legislature renamed it Clarke County in honor of William Clark. Land kept being split off until it reached its present area in 1880, and the spelling was corrected to Clark in 1925.
Now
With 503,311 people at the 2020 census, it is the fifth-most populous county in Washington.
Next
As part of a growing metro area, the county will likely keep facing hard choices about housing, roads and bridges.

Knowledge you can walk. Read the idea, then step up, across or down.

Clark County, Washington

Clark County is the southernmost county in Washington, across the Columbia River from Portland, with Vancouver as its county seat.

See it on the map

Learn, discuss, create, buy or invest

The idea

Clark County is the southernmost county in the U.S. state of Washington. It lies across the Columbia River from Portland, Oregon, and it is part of the Portland metropolitan area. Its county seat is Vancouver. A county seat is the town where a county's government has its main offices, such as its courthouse.

The Columbia River wraps around the county on two sides, and the North Fork of the Lewis River forms its northern edge. The flat land in the center and southwest of the county was carved by huge floods from the prehistoric Lake Missoula. These Missoula Floods were set loose thousands of years ago, as several ice dams melted.

Clark County was the first county in Washington. It was created by the Provisional Government of Oregon while the land was still part of Oregon Country, and at first it covered the entire present-day state. Its name honors William Clark of the Lewis and Clark Expedition. Since it once covered the whole future state, every other county in Washington was later formed from land that had started out as part of it.

Some residents cross the Columbia River to shop in Oregon, which has no sales tax. In 2019, about 65,000 Clark County residents commuted to work in Portland.

Check yourself

3 quick questions, instant feedback.