From Oregon Parks and Recreation Dept.:
Salem OR -- An extra 1,018 state park campsites were available for reservation starting 8 a.m. this morning, April 19, and by shortly after 9 a.m., they were all reserved. This includes all sites at 16 parks inside the "path of totality" plus space at 13 parks outside the path, where visitors will experience a partial eclipse. The eclipse will occur in the morning on August 21, 2017 and campsite reservations cover the nights of August 18, 19, and 20.
All reservations were completed within an hour and a half. A glitch at one park -- Unity Lake in Eastern Oregon -- caused problems for those 32 sites for about an hour. All state park sites available by reservation are now reserved, though cancellations may return a few sites to the pool. There is no waiting list, but campers can visit a state park's web page on https://oregonstateparks.reserveamerica.com/ and sign up to receive a notification about cancellations, then go online or call to try and reserve a space.
These extra 1,000+ sites were added to the reservation system by converting existing first-come/first-served campsites, parking areas, and other open spaces into reservable individual campsites just for the event. The Oregon Parks and Recreation Department does not expect to release any more new sites for reservations during the eclipse.
Campers who have a reservation along and near the path should continue to watch oregonstateparks.org for updates and planning tips.