Fort Clatsop was the encampment of the Lewis and Clark Expedition in the Oregon Country near the mouth of the Columbia River during the winter of 1805-1806. Located along the Lewis and Clark River at the north end of the Clatsop Plains approximately 5 mi (8 km) southwest of Astoria, the fort was the last encampment of the Corps of Discovery, before embarking on their return trip east to St. Louis.
The Lewis and Clark Expedition wintered at Fort Clatsop before returning east to St. Louis in the spring of 1806. It took just over 3 weeks for the Expedition to build the fort, and it served as their camp from December 8, 1805 until their departure on March 23, 1806.
The site is now protected as part of the Lewis and Clark National and State Historical Parks, and is also known as Fort Clatsop National Memorial. A replica of the fort was constructed for the sesquicentennial in 1955 and lasted for fifty years; it was severely damaged by fire in early October 2005, weeks before Fort Clatsop's bicentennial. A new replica, more rustic and rough-hewn, was built by about 700 volunteers in 2006; it opened with a dedication ceremony that took place on December 9.
The original Fort Clatsop decayed in the wet climate of the region but was reconstructed in 1955 from sketches in the journals of William Clark. The site is currently operated by the National Park Service.