Oregon has 98 public-use airports. These are open to any pilot, considering aircraft performance, without prior permission. With just over 1 airport per 1000 square miles, there are vast areas without a public airport available. We get a lot of inquiries about where else an aircraft can land. There are also 300 private airports in the state, but the owner's permission must be obtained to use them. Some of the owners or controlling agencies prohibit any other users except for emergencies.
A special notice, titled AIRCRAFT LANDING RESTRICTIONS, in the Airport/Facility Directory published by NOAA states:
"Landing of aircraft at locations other than public use airports may be a violation of Federal or local law. All land and water areas are owned or controlled by private individuals or organizations, states, cities, local governments, or U.S. Government agencies. Except in emergency, prior permission should be obtained before landing at any location that is not a designated public use airport or seaplane base." "Landing of aircraft is prohibited on lands or water administered by the National Park service, U.S. Fish and Wildlife Service, U.S. Forest Service, and on many areas controlled by the U.S. Army Corps of Engineers, unless prior authorization is obtained from the respective agency."
We get frequent questions about landing on the beach. The long stretches of smooth sand are inviting. However, landing on the beach, except in an emergency, is specifically prohibited by ORS 836.510. The coastal police departments are very aware of this and enforce it vigorously. Also, ORS 837.090 prohibits landings on public highways and other public grounds without the permission of the authorities in charge. Seaplanes can generally operate on bodies of water where motor boats are allowed. Once they are on the water they are considered to be boats, but land planes have no such privilege.
The key to landing anywhere not designated as a public-use airport, is to obtain prior permission, whether it be from the responsible private owner or public agency. No further approval is needed as long as such use is on an occasional, infrequent basis (as determined by the Department of Aviation). Of course, the user assumes all risks and liabilities. If the use is more than occasional, an airport Site Approval from ODA is necessary.