Prior to the Europeans' arrival to the area, it was inhabited by numerous Native American tribes, with the Cowlitz tribe being the largest. They were drawn to the region by the abundance of
salmon. The Cowlitz are considered to be the first regional inhabitants to engage in commerce as they traded extensively with other tribes in
Western and
Eastern Washington. The Cowlitz Indian population declined significantly from the 1829-1830
smallpox outbreak. European explorers discovered and began navigating the
Columbia River in 1792 as
British Lieutenant W. R. Broughton sailed up the river to and past present-day Cowlitz County. Then on November 5, 1805,
Lewis and Clark camped at the mouth of the
Kalama River. Over the following days, they reached the present sites of Kelso and Longview. By the 1820s, the
Hudson's Bay Company had established a lucrative
fur trade in the region. Furs were shipped down the
Cowlitz River to the Columbia, where they were loaded and shipped around the world. Trade declined significantly in the late 1830s, as overhunting reduced the annual yields, and wearing fur had become less fashionable. During the next several decades, white settlement of the region was in full swing. Most of the settlers homesteaded near the tributaries that fed the Columbia River, forming settlements. The first was Monticello, near present-day Longview. In 1841, several families with the HBC directed
Sinclair expedition from
Red River Colony settled there. On November 25, 1852, at Monticello, settlers from the Cowlitz and
Puget Sound regions drafted a petition (the
Monticello Convention) to the federal government, calling for a separate territory north of the Columbia River to be carved out of the existing
Oregon Territory. The petition was successful; three months later, the
United States Congress formed the Columbia Territory, although it was soon renamed
Washington Territory. The newly separated territory was governed by two existing counties. In August 1845, the Oregon territorial government had created Vancouver County. Its boundary covered the entire area of present-day Washington. In December of that same year, the Oregon territorial government sliced off the eastern portion to create
Lewis County. In 1849, the reduced Vancouver County was renamed
Clark County. When the new Washington territorial government began functioning, among its first actions was the creation of Cowlitz County from the southwestern portion of Clark County. This proclamation was finalized on April 24, 1854, signed into law by Governor
Isaac Stevens. Later in 1854, the western portion of the new county was partitioned off to form
Wahkiakum County; otherwise, the county's boundary has remained unchanged until the present. Nearly every town that sprang up in the late 19th century began around a
logging or
lumber-milling operation. In the latter half of the 1920s, the
Weyerhaeuser Company and
Long-Bell Lumber Company established processing facilities. At the time, these two facilities were the first- and second-largest in the world. The county is still heavily dependent on the timber industry. Four towns have functioned as the Cowlitz County seat: •
Monticello (1854–1865) •
Freeport (1865–1872) •
Kalama (1872–1922) •
Kelso (1922–Present) ==Geography==