Loon Lake is a 294 acres (119 ha) lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 located in Douglas County

Douglas County, Oregon

-National protected areas:* Crater Lake National Park * Rogue River-Siskiyou National Forest * Siuslaw National Forest * Umpqua National Forest * Willamette National Forest -Adjacent counties:* Lane County, Oregon -...

 in the Oregon Coast Range

Oregon Coast Range

The Oregon Coast Range, often called simply the Coast Range and sometimes the Pacific Coast Range, is a mountain range, in the Pacific Coast Ranges physiographic region, in the U.S. state of Oregon along the Pacific Ocean...

 of the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

,15 miles (24.1 km) east-southeast of Reedsport

Reedsport, Oregon

Reedsport is a city in Douglas County, Oregon, United States. As of the 2010 census, the population was 4,154.- History :Reedsport was established on the estuary of the Umpqua River on January 7, 1852. It was named for a local settler, Alfred W. Reed, who founded the city in 1912...

, Oregon

Oregon

Oregon is a state in the Pacific Northwest region of the United States. It is located on the Pacific coast, with Washington to the north, California to the south, Nevada on the southeast and Idaho to the east. The Columbia and Snake rivers delineate much of Oregon's northern and eastern...

 at an elevation of 392 feet (119 m).. The lake is about two miles (3 km) long with a maximum width of about 0.4 mile (0.6 km), and is over 100 feet (30.5 m) deep in some places.

The lake is "a classic example of a landslide lake", dammed by a slide of sandstone

Sandstone

Sandstone is a sedimentary rock composed mainly of sand-sized minerals or rock grains.Most sandstone is composed of quartz and/or feldspar because these are the most common minerals in the Earth's crust. Like sand, sandstone may be any colour, but the most common colours are tan, brown, yellow,...

 blocks which fell into the Lake Creek valley about 1400 years ago.