Wild, Wild Research in the Mountain West States

Wild, Wild Research in the Mountain West States ©

By Dayna Jacobs, AG® www.ongrannystrail.com

(You are welcome to copy this for your own use, but please do not publish it online or copy for distribution to others. Thank you!)


Research in the Mountain West States (Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, Wyoming) requires  thinking on a large scale; the area stretches from Canada  to Mexico,  was part of six countries’ histories  (Spain, Mexico, France, Great Britain, Republic of Texas, and the United States) and had a large native population with its own history.  The climate and geography vary on the broadest scale, from snowy mountaintops and plains to hot, arid, deserts and valleys.

Modern-day boundaries for the United States, excluding Alaska and Hawaii, were finalized with the Gadsden Purchase in 1853.  For the next 15 years the territory west of the Mississippi River invented and reinvented itself as various individual territories emerged, grew, divided, and by 1868, finally settled on boundaries familiar to us.  Of the eight “Mountain West States,” the first to achieve statehood was Nevada (1864), and the last were Arizona and New Mexico (1912).

The western United States was first inhabited by Native Americans.  The first foreigners to arrive and establish permanent settlements were Spaniards who established a trade route from Mexico City to what is now Santa Fe, New Mexico in 1598.  By the time English settlers founded Jamestown, Virginia in 1607, San Juan Pueblo , just north of Santa Fe, was nearly ten years old, and by the American Revolution in 1776 Spain owned essentially all land west of the Mississippi River.  Mexico’s independence from Spain in 1821 gave it jurisdiction over the Southwest until the conclusion of the Mexican War in 1848.  The Treaty of Guadalupe Hidalgo transferred land in what is now California, Nevada, Arizona, New Mexico, Utah, Texas and Colorado to the United States. What are now Idaho, Oregon, Washington, and part of Montana were under British rule until 1846.  Until the Louisiana Purchase in 1803 part of what is now Montana, Wyoming, and Colorado was French, but was originally claimed by Spain.

As one can see, the search for records in the Mountain West States requires not only an understanding of the area’s history, but a set of very good maps!


There were so many boundary and government changes for the Mountain West States, the first step in research is to determine jurisdiction:  Spain, Mexico, Great Britain, France, the Republic of Texas, or United States territory or state. After 1848 this region was under control of the United States (except for a southern sliver of Arizona and New Mexico), but territorial government preceded state government, so know where to look for territorial records.  Be aware that in the 1850s territorial boundaries encompassed large areas—greater than what would finally be defined in statehood. Know where to look for the records you seek—territorial, state, or federal.

If a locality and time period can be identified for an ancestor, use Animap or online maps at University of Texas Perry-Castañeda Library Map Collection to answer these questions:

  • What country had jurisdiction ?
  1. What territory or state had jurisdiction?

Once a territory became a state, territorial records were archived with the federal government, and record-keeping on a state level began.  Find territorial records in NARA regional archives, or microfilmed copies at State Archives and university collections.  FHL has NARA microfilm—search “Territorial papers.”


Because traditional records may not exist in the West, these record groups are essential:

1.  Maps— historical boundaries, topographical, cadastral, Spanish and Mexican land grants

2. Land and property—l and entry files, tract books, deeds, mining records,  3. Church records—particularly Catholic and Church of Jesus Christ of Latter-day Saints

4.  Congressional records—U.S. Congressional Serial Set and American State Papers

5.  Newspapers—frontier papers may predate other records

6.  Court—disputes over water rights, boundaries, mining claims, territorial lawlessness

7. Bureau of Indian Affairs (BIA)—White settlers interacted with Indians regularly and Indian Agents sent frequent reports to headquarters

8.  Diaries and journals—pioneers chronicled their journeys and traveled in groups.


Mountain West States research requires familiarity with state archives, NARA’s regional facilities, university special collections, and libraries specializing in the Southwest.   Utilize online consortia.


–        Tribal

–        Colonization by other countries

–        Trappers and explorers

–        Religious groups

–        Miners

–        Frontier military/forts

–        Federal land acts

–        End of the Civil War

–        Railroads


Rivers and their tributaries

–        Missouri

–        Platte

–        Rio Grande

–        Colorado

–        Arkansas

–        Snake


–        Northern Pacific (1883) – Saint Paul and Minneapolis, MN to Portland, OR

–        Union Pacific/Central Pacific (1869) – Omaha, NE to San Francisco (Golden Spike in Promontory, UT)

–        Union Pacific Kansas – Topeka, KS to Denver

–        Southern Pacific (1883) – New Orleans to El Paso, to Los Angeles

–        Atchison-Topeka-Santa Fe (1881) – Atchison and Topeka, KS to Santa Fe, NM

–        Denver Rio Grande – Denver to Santa Fe


  • Library of Congress Map Collection                                                                                   Click on Digital Collections>Map Collections
  • USGS Topographical Maps – download or print          Click on Maps, Imagery, and Publications >USGS Store>Map Locator>Search on right side>click on red balloon
  • National Atlas printable outline maps of federal land and Indian reservations, rivers and water bodies, cities and capitals, and territorial acquisition
  • Library of Congress.  Geography and Map Division. Land Ownership Maps.  Washington, D.C.: L.O.C., 1983.  2010 FHL microfiches:  First fiche #6079238; Checklist: 6048262.  [covers 1840-1900]
  • Hargett, Janet L., compiler.  List of Selected Maps of States and Territories. Washington, D.C.: NARA, 1971. Historical maps can be ordered from vendors:
  • State Archives – many have online map collections
  • Animap software by Goldbug Software




  • Familysearch Record Search  Scroll to state.  Digital images and indexes of vital records.
  • Linkpendium      Click state.  Search under “Statewide resources” and individual counties.  


  1. American State Papers. 38 vols.  Washington, D.C.:  Gales and Seaton, 1832-1861 [covers  1789-1838]
  2. Beers, Henry P.  Spanish and Mexican Records of the American Southwest: A Bibliographic Guide to  Archive and Manuscript Sources.  Tucson, Arizona:  University of Arizona Press, 1979.
  3. Billington, Ray Allen. Westward expansion : a history of the American frontier.  New York, NY:  Macmillan Publishers Limited, c1982.
  4. Flanders, Stephen A. Atlas of American Migration. New York, NY:  Facts on File, 1998.
  5. Hart, Herbert M. Old Forts of the Southwest. New York: Bonanza Books, 1964.
  6. Hill, Edward E., comp. Records of the Bureau of Indian Affairs. Washington, D.C.:  NARA, 1965.
  7. Hone, E. Wade. Land and Property Research in the United States.  Salt Lake City, UT: Ancestry, 1997.
  8. Kvasnicka, Robert M. comp. The Trans-Mississippi West 1804-1912. 4 parts. Washington, D.C.: NARA,  1993-1997.
  9. McMullin, Phillip W., editor.  Grassroots of America:  Index to American State Papers, Land Grants &  Claims, 1789-1837. Greenville, South Carolina:  Southern Historical Press, 1990.
  10. Modelski, Andrew M.  Railroad Maps of North America:  The First Hundred Years. Washington, D.C.:  Library of Congress, 1984.
  11. Swanton, John R.  Indian Tribes of North America.  Washington, D.C.: Smithsonian Inst. Press, 1952.
  12. Twitchell, Ralph E. Spanish Archives of New Mexico. V. 1-2. Cedar Rapids, IA: Torch Press, c1914.
  13. United States Congressional Serial Set .  Washington, D.C.: U.S. G.P.O. [Began with: No. 1, with the 15th Congress, 1st session, 1817]
  14. Wexler, Alan.  Atlas of Westward Expansion. New York, NY:  Facts on File, 1995.
  15. Williams, Jerry L. New Mexico in Maps.  Second edition.  Albuquerque, NM:  UNM Press, c1986.



1849 California

1850 Queen Charlotte, B.C.

1850 Northern Nevada

1856-1858 Arizona (silver)

1858-1961 British Columbia

1858 Cherry Creek (Denver)

1859 Pike’s Peak, Colorado

1859 Virginia City, Nevada

1860 Idaho

1863 Black Hills, Montana

1860s/1870s East. Oregon

1870s Leadville, Colorado

1870s – 1880s Arizona

1890s Silver at Creede, Gold at Cripple Creek, CO

The ICAPGen ℠ service mark and the Accredited Genealogist® and AG® registered marks are the sole property of the International Commission for the Accreditation of Professional Genealogists.  All Rights Reserved.

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