Map - Tillamook County, Oregon (Tillamook County)

Tillamook County is one of the 36 counties in the U.S. state of Oregon. As of the 2020 census, the population was 27,390. The county seat is Tillamook. The county is named for the Tillamook or Killamook people, a Native American tribe who were living in the area in the early 19th century at the time of European American settlement. The county is located within Northwest Oregon.

The Tillamook were the southernmost branch of the Coast Salish. They were separated from their more northern kinsmen by tribes speaking the Chinookian languages. The name Tillamook is of Chinook origin (a trade pidgin, which had developed along the lower Columbia.) According to Frank Boas, "It [Tillamook] means the people of Nekelim. The latter name means the place of Elim, or in the Cathlamet dialect, the place of Kelim. The initial t of Tillamook is the plural article, the terminal ook the Chinook plural ending —uks." Since there was one village in the area of Nehalem bay; the area was referred to as Nekelim (Ne Elim=singular). There were at least four villages on the south Tillamook bay according to Lewis and Clark; the south bay was called "T-Elim-ook" (the plural of Elim), meaning many villages of Elim. (The Chinook word for water was "chuck" and the Salish word for wetland is "naslex". The popular translation of Tillamook as meaning "land of many waters" seems to be 20th-century fabrication used in the tourist industry.)

Tillamook County, the 12th county in Oregon to be organized, was established on December 15, 1853, when the Territorial Legislature approved an act to create the new county out of an area previously included in Clatsop, Yamhill and Polk counties. Boundary changes were enacted with Clatsop County (1855, 1870, and 1893), Lincoln County in 1893, Washington County (1893, 1898), and Yamhill County (1887).

The Coast Range behind Tillamook was the scene of a repeated series of forest fires called the Tillamook Burn between 1933 and 1951. In 1948, a state ballot approved the sale of bonds to buy the burned-over areas and have the state rehabilitate the lands. The state lands were renamed the Tillamook State Forest by governor Tom McCall on July 18, 1973. By the end of the 20th century, the replanted growth was considered mature enough to be commercially harvested.