Koosah Falls, Waterfall in Willamette National Forest, Oregon, United States.

Koosah Falls, also called Middle Falls, is the second of the three major waterfalls on the McKenzie River in Willamette National Forest, Linn County, Oregon. Its main drop of 64 feet (20 m) plunges into a large pool, 0.5 miles (0.8 km) downstream south of Sahalie Falls and south of Santiam Pass.

Koosah Falls is the second of the three major waterfalls on the McKenzie River, 0.5 miles (0.80 km) downstream from Sahalie Falls. The name comes from Chinook Jargon, in which koosah means "sky"; the falls are also called Middle Falls. The site lies in the Willamette National Forest in Linn County, Oregon, south of Santiam Pass.

Koosah is a Chinook Jargon word meaning "sky", the name given to the second of the three major waterfalls on the McKenzie River; it is also called Middle Falls. The falls lie 0.5 miles (0.80 km) downstream south of Sahalie Falls, in the Willamette National Forest in Linn County.

Koosah Falls sits on the McKenzie River 0.5 miles (0.8 km) downstream south of Sahalie Falls, reached from Highway 126 southeast of Salem and northeast of Eugene. The trail along the river links the two falls, so the drop is seen on foot rather than from the road.

Koosah Falls is also called Middle Falls because it is the second of the three major waterfalls on the McKenzie River, sitting 0.5 miles (0.80 km) downstream from Sahalie Falls. Its name comes from Chinook Jargon, in which koosah means "sky".