- Don’t have time to visit Washington’s wild and scenic backcountry? Some of the exciting geology Washington has to offer may be just a stone’s throw away from your home. Lake Sammamish, a popular suburban beach getaway, lies just to the east of Seattle. At the lake’s southern end, Lake Sammamish State Park boasts a whole array of activities on water and land for the whole family. It’s certainly worth a day trip. For a geology-enthusiast, however, a pleasant afternoon by the lake can also involve imagining what the valley looked like during the last ice age. Take a break from paddling and picnicking to think about how geologic forces created this well-loved recreation area.