This page shows the county boundaries at each US Census pertinent to present day Idaho, and at the formation of the Territory of Idaho. International visitors may want to see where Idaho is on this map of the United States of America

	1850  Oregon Territory was established in 1848 and included all of present-day Idaho.
	1860  The area north of 46o latitude was part of Spokane County, Washington. Some people living in the Bear Lake area were enumerated as part of Cache County, Utah.
	1863  Idaho Territory was organized in 1863. For more information see Idaho Territorial Voters Poll Lists 1863, Transcribed, Edited and Indexed by Gene F. Williams, Boise, ID 1996. Click here to see the map and key from Gene's book, used by permission. 1. Shoshone, 2. Nez Perce, 3. Idaho, 4. Boise, 5. Missoula, 6. Other
	1870  Parts of extreme southeast Oneida County were enumerated as part of Cache and Rich counties in Utah Territory. Unorganized Kootenai County was enumerated with Nez Perce County.
	1880 Yellowstone National Park was created in 1872 cutting a small slice out of the extreme northeast corner of Oneida County. Any persons enumerated within this area are found in the Wyoming census from that year forward.
	1890  Idaho became a state in July 1890. The federal census was lost for all counties. Logan and Alturas counties were abolished in 1895.
	1900 Bannock, Bingham and Nez Perce Indian schedules were microfilmed immediately following Washington County. 1. Kootenai, 2. Latah, 3. Shoshone, 4. Nez Perce, 5. Idaho, 6. Lemhi,7. Washington, 8. Boise, 9. Custer,10. Fremont, 11. Canyon, 12. Ada,13. Blaine, 14. Bingham, 15. Lincoln,16. Owyhee, 17. Cassia, 18. Oneida,19. Bannock, 20. Bear Lake, 21. Elmore.
	1910 An "every name" index exists for 1910, Idaho. 1. Bonner, 2. Kootenai, 3. Shoshone, 4. Latah, 5. Nez Perce, 6. Idaho,7. Washington, 8. Boise, 9. Custer,10. Lemhi, 11. Canyon, 12. Ada,13. Elmore, 14. Blaine, 15. Fremont,16. Lincoln, 17. Bingham, 18. Owyhee,19. Twin Falls, 20. Cassia, 21. Oneida, 22. Bannock, 23. Bear Lake
	1920 Most of the modern county lines were set by 1920, but please note the unfinished boundaries of Ada, Elmore, Owyhee, Custer, Butte, Bannock, Caribou, Franklin, & Oneida counties.

Idaho State Coordinator Mike St. Clair	© 2009, 2010 - This page was last modified 25 July 2009.	Assistant State Coordinator Mitch Ryder
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