Plymouth Park Boat Ramp provides protected access to Lake Umatilla on a small island, featuring a single boat launch with a courtesy dock for shore fishing and ample parking at the day-use area.

The ramp is located approximately one mile from the main campground and offers amenities including restrooms, picnic tables, and a swim beach, making it ideal for both paddlers seeking calm water and anglers.

The facility operates seasonally from April 15 through October 15 and is managed by the U. S. Army Corps of Engineers.