[1] It lies east of Lake Washington and west of the Sammamish Plateau, and stretches from Issaquah in the south to Redmond in the north.

[1] Loose, sponge-like forest soils virtually eliminated runoff during winter storms and recharged groundwater aquifers which then released fresh water to streams in the dry summer months.

[2][3] In May, 2010 the federal government asked the town of Sammamish to restrict development within 250 feet (76 m) from the lakeshore to protect local salmon and steelhead (Oncorhyncus mykiss) species.

On July 6, 2010, officials of the City of Issaquah asked Washington Department of Fish and Wildlife to tear out a beaver dam on Tibbetts Creek in Lake Sammamish State Park because of concerns about potential flooding and barriers to salmon migration.

[8] In contrast, research on watersheds in the Northern United States and Canada shows that beavers provide ecological benefits by creating ponds that increase fish and bird abundance and diversity.

[9] Research in the Stillaguamish River basin, approximately 50 miles (80 km) north of Lake Sammamish, found that extensive loss of beaver ponds resulted in an 89% reduction in coho salmon smolt summer production and an almost equally detrimental 86% reduction in critical winter habitat carrying capacity.