The Comprehensive Plan guides the growth of unincorporated Thurston County (areas outside of the cities). It details policies and goals for zoning and development regulations, and addresses requirements of Washington state's Growth Management Act
. It also includes specific guidelines
for the subareas of Grand Mound, Rochester and Nisqually, as well as Joint Plans for the Urban Growth Areas (UGAs) of Lacey, Olympia, Rainier, Tenino, Tumwater, and Yelm. The plan was most recently updated in December 2020 to plan for population growth to 2040.
Citizens may propose changes to the plan through a process called Comprehensive Plan Amendment.