Marion Reservoir will benefit from a $6 million federal project, Ranger Traci Robb said.
The project is part of the federal stimulus program.
About $5 million is set aside for modernization at Cottonwood Point. A new camping loop will be added with up to 60 campsites, a new swimming beach, shower and bathroom facilities, and a day-use area.
The day-use area will be the first at the park, Robb said. When the park is full of campers, families can have difficulties finding places for a single-day picnic.
Another $620,000 will pay for asphalt repair in the four main parks: Cottonwood Point and Hillsboro, Marion, and French Creek coves.