- Martha Lake Airport Park is a county park located in Martha Lake, Snohomish County, Washington. It was originally a private-use airport known as the Martha Lake Airport that was closed in the late 1990s and sold to the county in 2000. The 28.76-acre (11.64 ha) park was opened in 2010 and features athletic fields for soccer and softball and a skate park. A large glacial erratic on the property, one of several in the county, is used for bouldering (rock climbing).