Mountlake Terrace is a city in Snohomish County, Washington, United States. It is a northern suburb of Seattle and lies north of Shoreline and Lake Forest Park, east of Edmonds, south of Lynnwood, and west of Brier. Its southern boundary runs along the King County line. Interstate 5 runs north-south through the city, and services the city via three exits. The population was 19,909 at the 2010 census.HistoryThe site of Mountlake Terrace was thickly forested in the mid-Nineteenth Century and formed part of the traditional hunting-gathering areas of the Snohomish people. The area was obtained by the Puget Mill Company in 1862. By 1900, most of the land in south Snohomish County had been logged. Pope & Talbot Company, the successor entity of the Puget Mill Company, subdivided the cut area into 10-acre plots, which were sold as "chicken ranches." These plots were sold with moderate success to ranchers raising poultry, mink, and chinchilla. An interurban rail line between Tacoma, Washington and Everett, Washington was built in 1910, allowing easier access to the farms from throughout the region. Many of them failed during the Great Depression, however, and the railroad was abandoned in 1939.