The Willamette Falls Locks are a canal lock system built around the falls to allow river navigation past the cascade. Completed in 1873, they are the oldest multi-lift navigation locks still in existence in the United States. The locks enabled steamboat and barge traffic on the upper Willamette River, opening the interior of Oregon to commercial development.
Today the locks are managed by the US Army Corps of Engineers, and while commercial traffic has long since ended, pleasure craft can still use them. The surrounding area is part of the broader Willamette Falls riverfront restoration project. The locks themselves are a handsome piece of 19th-century civil engineering and worth seeing if you have any interest in industrial history or waterway infrastructure.