The area was an unincorporated area within King County until it incorporated as a city on September 30, 1994. Currently the city is a suburban community. Based on Newcastle's location north of Renton, south of Bellevue, and across Lake Washington from Seattle, these are the communities in which most of the residents of Newcastle work. East of southeast Lake Washington is a large quantity of hilly terrain, which creates opportunities for view properties. This created the impetus for the location of the Newcastle Golf Course, along with many high-value homes at higher elevations with views of downtown Bellevue, Seattle, and Mercer Island, as well as the Olympic Mountains. Notable attractions of the area include the Golf Club at Newcastle, a brand new Family YMCA, Lake Boren Park, a well developed trail system, and nearby Cougar Mountain in the east of Newcastle.