Lochsloy is a census-designated place in Snohomish County, Washington, United States. The population was 2,533 at the 2010 census. Lochsloy is located in northwest Washington. Lochsloy has 7.46 square miles of land area and has no water area. As of 2010-2014, the total Lochsloy population is 2,584, which has grown 21.03% since 2000.