Thurston County is over 700 square miles in area. Its topography ranges from the Cascade foothills in the southeast, to prairie flatlands, to the coastal lowlands on the Puget Sound. With over 18 square miles, Olympia is the largest jurisdiction; with just 0.6 square miles, Bucoda is the smallest.
In 1859, Olympia became the first town in Thurston County to incorporate. Lacey is the County's newest city, incorporating in 1966. Thurston County's cities and towns continue to expand by annexing new areas. For more information about the annexation process, visit the Thurston County Boundary Review Board website.