Tillamook County is a county located in the U.S. state of Oregon. As of the 2010 census, the population was 25,250. The county seat is Tillamook. The county is named for the Tillamook, a Native American tribe who were living in the area in the early 19th century at the time of European American settlement.
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), with Lincoln County in 1893, Washington County (1893, 1898), and with Yamhill County in 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.
The Tillamook airbase for blimps was commissioned on December 1, 1942, as U.S. Naval Air Station Tillamook. The two hangars were closed after World War II and sold. One of the hangars was destroyed by a fire in 1992 and only two posts now remain. The surviving blimp hangar is a local landmark and the location of the Tillamook Air Museum.
The U.S. Mount Hebo Air Force Station was a Cold War air defense installation from 1956 to 1980. Located south of Tillamook, at the top of high Mount Hebo, Air Force radars operated by the 689th Radar Squadron and the 14th Missile Warning Squadron were essential parts of the nation's integrated air defenses. The large radomes protecting the radars from adverse weather effects could be seen silhouetted against the sky from most of Tillamook County.
Development along U.S. Route 101 to the north of Tillamook during the last part of the 20th century has blocked part of the flood plain of the Wilson River, contributing to repeated winter flooding in the city.