Lake Sammamish State Park, State park near Lake Sammamish in Issaquah, United States.

Lake Sammamish State Park covers 512 acres at the south end of Lake Sammamish, with 6,858 feet of waterfront where Issaquah Creek enters the lake. Its facilities are grouped in three areas: west of the creek lie Tibbetts Beach, Sunset Beach, picnic shelters and athletic fields; east of the creek are a boat launch and trails; east of East Lake Sammamish Parkway SE is the Hans Jensen Youth Camp.

The Snoqualmie, Sammamish and Duwamish fished, hunted and gathered camas in the prairie and old-growth forest of the Issaquah Creek valley, which reached the lake's southern shore. From the 1860s hunters, miners and settlers arrived from the Bellevue area, and by the late 1800s the park's cedars and firs were cut and floated to sawmills at the lake's north end, followed by hop and dairy farms.

The park lies in the Issaquah Creek valley where descendants of the Snoqualmie, Sammamish and Duwamish fished, hunted and gathered camas in the prairie and old-growth forest. From the 1860s settlers logged the cedars and firs, floated them to sawmills at the lake's north end, then farmed hops and dairy on the cleared land.

Access is from Interstate 90 exit 15 and the north end of State Route 900; local routes are East Lake Sammamish Parkway SE and NW Sammamish Road. About 250 trailer-combination parking stalls are provided, with separate lots near each soccer field group. Metro Transit routes 200, 216, 217 and 927 serve the park. Swimming areas are cold even in summer, and the boat launch lies east of Issaquah Creek.

The park sits at the center of a dispute over the ecological benefits of beavers. Archaeologists have also mapped trees on the lake bed more than 1,100 years old, submerged by earthquakes and landslides; similar slides struck Lake Washington at about the same time.