This maps shows City of Boise annexations since the original townsite was established in 1866 by the Idaho Territorial Legislature. Use the time-slider to watch the City grow over time.

This maps shows City of Boise annexations since the original townsite was established in 1866 by the Idaho Territorial Legislature. Use the time-slider to watch the City grow over time. An annexation is the legal incorporation of a geographic area in to a political body. A de-annexation is the secession of a geographic area from a political body. De-annexed areas are areas that were once part of the incorporated boundaries of Boise City but have been removed from the incorporated boundaries (based on the ordinance tied to the de-annexation). The source of the data is the ordinances of annexation recorded by the Boise City Clerks' office. The map also depicts the current incorporated boundaries for cities within Ada County. The Ada County Assessor's Office maintains the city limits and impact areas datasets within Ada County. City boundaries are determined by taxcode and maintained continually, adding areas annexed to city limits by current ordinances. The impact areas dataset depicts the unincorporated areas of Ada County surrounding each city as identified in Title 9 of the Ada County Code, in accordance with Idaho Code Section 67-6526. This data is maintained by City of Boise GIS and is based on the legal descriptions contained in the ordinances. This data set is continually being updated as annexations occur. It is current to the date it was published.For more information, please contact the Ada County Assessor's Division of Land Records/GIS or the City of Boise Planning & Development Services division.