Mountlake Terrace is a city in Snohomish County, Washington, United States.The population was 19,909 at the 2010 census.
The 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. In 1949, developers Albert LaPierre and Jack Peterson. Bought the abandoned airstrip and began constructing cinder-block houses. They named their development "Mountlake Terrace" because from some parts of the property they could see both Mount Rainier and Lake Washington, and the old runway looked a little like a terrace.