The US Census Bureau conducts the Boundary and Annexation Survey (BAS) annually to collect information about selected legally defined geographic areas. The information collected in this survey is used to update information about the legal boundaries and names of all governmental units in the United States. UGRC has a unique role in the completion of the BAS; in accordance with an agreement between Utah and the US Census Bureau, UGRC shares Utah’s data from the State Geographic Information Database (SGID).

In the past, local and county governments would submit their own data to the Census Bureau and try to ensure that the legal boundaries and official names for their localities were correct. But this system presented certain challenges—if the boundary and name information was incorrect or outdated, it would affect official population counts, and many government agencies and other groups use those population counts to determine the allocation of funds.

With the current agreement between Utah and the Census Bureau, the previous issue of potentially incorrect data has been addressed. Utah State Code requires local and county governments to submit their changes through the Lieutenant Governor’s Office. As town, city, and county recorder’s offices submit information about annexations, disconnections, and incorporations throughout the year, UGRC reviews the plat map information and then adjusts and adds the boundaries to the SGID. Then the UGRC will compile all of those changes and submit the comprehensive, updated state data for the BAS at the end of each year.

If you’re interested in seeing what the SGID currently shows for your town, city, or county, check out the online Utah Municipality Modifications map. UGRC is working on updating the boundaries before the 2020 Census, so the Utah Municipality Modifications map is up to date and will stay that way.

On the left, you’ll see the legend, which shows modifications for 2017 and 2018 and the current boundaries for municipalities and metro townships. If you want to see previous years’ boundaries, go to the Content tab. Under that tab, the data from 2013 through 2016 is broken out by year, and data from before 2013 is shown when you select the “MunicipalitiesModificationsPriorTo2013” box. The content boxes can be turned on and off as desired.