Although Newcastle was not incorporated until 1994, it has been an important settlement and town since the late 19th century and played a major role in the development of Seattle and the Seattle region. Newcastle was one of the region's earliest coal mining areas and its railroad link to Seattle was the first in King County. Timber also played a role in the early history of Newcastle. Coal delivered by rail from Newcastle's mines to Seattle fueled the growth of the Port of Seattle and attracted railroads, most notably the Great Northern Railway.
The Newcastle coal mine began producing coal by the 1870s. More than 13 million tons of coal had been extracted by the time the mine closed in 1963. The history of Newcastle's coal mining industry and the legacy of the mines' many Chinese laborers are memorialized in place names such as Coal Creek, Coal Creek Parkway, and the Coal Creek and China Creek Golf Courses.
Based on per capita income Newcastle ranks 11th of 522 areas in the state of Washington to be ranked. In CNN Money's 2011 rankings of best places to live in the United States, Newcastle was in the top 20, along with nearby Sammamish. In Newsweek's 2009 rankings of best places to live in the United States, Newcastle was honored with the 17th spot.
Newcastle was named after Newcastle upon Tyne in England, as it was originally a coal mining town founded in the 1870s. Coal was discovered along Coal Creek in 1863. The surveyors Philip H. Lewis and Edwin Richardson made the discovery while surveying the area for the General Land Office. By 1872 75-100 tons of coal per day were being produced at Newcastle. About 60 men worked at the mines. The Seattle and Walla Walla Railroad, the first railroad in King County, was built from Seattle to Newcastle in the late 19th century. Coal mining ended in 1963.
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.