Fort Clatsop, Historic winter fort in Astoria, United States.

Fort Clatsop is a reconstruction of the 1805–1806 winter encampment of the Lewis and Clark Expedition, on the Lewis and Clark River about 5 miles southwest of Astoria, Oregon. It is built of horizontal unpeeled logs with pale log ends at the corners, in two adjoining sections with low-pitched roofs. A narrow vertical plank door with a diagonal brace and a projecting round-log frame opens the left section; two cylindrical log stumps stand in front.

The original structure was built in the winter of 1805 and 1806 when an expedition led by William Clark and Meriwether Lewis stayed there. The current fort was rebuilt in 2006 following a fire and follows historical records.

The fort takes its name from the Clatsop people who lived in the region and helped guide the expedition through unfamiliar territory. The wooden structures reflect how shelter and daily routines were organized during a winter spent far from home in the early 1800s.

The visitor center offers films and exhibits about the expedition and life on the Pacific coast, while rangers regularly conduct demonstrations inside the fort itself. The site is located in wooded terrain with walking paths along the river.

The 2005 fire was reported as smoke, but a dispatcher mistook it for rising fog, delaying the fire brigade; most of the replica burned. Rebuilding began at once with public support, and about 700 volunteers raised the new fort, dedicated on December 9, 2006.