Tiernan Boat Ramp is a day-use boat launch located near Mapleton on the Siuslaw River, approximately five miles west on Oregon Route 126, featuring a large parking lot suitable for turning around with truck and boat trailers.

The facility includes a single boat ramp, portable restroom, and parking for 10 cars and trailers. Day-use access is open year-round from dawn to dusk with a day pass or annual pass required (payable via the Passport Parking App).