Issaquah is surrounded on three sides by what are known locally as the Issaquah Alps: Cougar Mountain on the west, Squak Mountain to the south, and Tiger Mountain to the southeast. To the north of Issaquah is Lake Sammamish. Cougar and Squak Mountains are home to sizable neighborhoods on their lower slopes, though the bulk of all three mountains are preserved in public ownership as Squak Mountain State Park, Cougar Mountain Regional Wildland Park, West Tiger Mountain NRCA, and Tiger Mountain State Forest. Geologists have noted the chemical and geological content of these three mountains to be much different from that of the Cascade Range, because they are not volcanic in origin, while the entire Cascade Range is postulated to have formed from volcanic action. They believe that these three mountains are the remains of a much older mountain range long since eroded by earthquakes, volcanic action, and shifting plates.