Lacey is a city in Thurston County, Washington State, USA. Established as a suburb of Olympia, Lacey's population as of the 2000 census was 31,226, as compared to 42,514 for Olympia. This makes Lacey less of an Olympia suburb and more of a city in its own right. Thurston County, which includes the cities of Lacey, Olympia and Tumwater, has a population of 207,355 as of the 2000 census.