Marymoor Park (Wikipedia) Marymoor Park, located on the north end of Lake Sammamish in Redmond, Washington, is King County’s largest, oldest, and most popular park, with more than 3 million annual visitors coming to roam its 640 acres (2.6 km2). Among recreational activities available are various sports facilities, rock climbing, a 40-acre off-leash dog park and a velodrome. It is also one end of the Sammamish River Trail, a biking and walking trail. In addition, a radio control aircraft flying field and a pet memorial garden are within the park’s boundaries.