Question: In which territory or state is the former county that the most populous county in its territory or state ?

text: List of counties in Colorado
Former counties
The sortable table below lists all the historic counties of the Territory of New Mexico , the Territory of Utah , the Territory of Kansas , and the extralegal Territory of Jefferson [ 20 ] that previously existed within the boundaries of the present State of Colorado , as well as the three defunct counties of the Territory of Colorado and the three defunct counties of the State of Colorado . The table includes the following information :
The U.S. state of Colorado is divided into 64 counties. Counties are important units of government in Colorado since there are no townships or other minor civil divisions. Two of these counties, Broomfield and Denver, have consolidated city and county governments. Colorado's ISO 3166-2:US state code is CO and its ANSI INCITS 38:2009 state code is 08. When the Colorado Territory first began creating counties in 1861, 17 counties (Summit, Larimer, Weld, Boulder, Gilpin, Clear Creek, Jefferson, Arapahoe, Douglas, Lake, Conejos, Costilla, Park, Fremont, El Paso, Pueblo, and Huerfano) and a Cheyenne Reserve were formed. In February 1866, the first new county, Las Animas, was created, followed by Saguache in December of that year. Bent County was created in February 1870, followed by Greenwood the following month. On February 2, 1874, Grand County and Elbert County were formed, and on February 10, La Plata, Hinsdale, and Rio Grande counties were created. Greenwood was absorbed into Bent on February 5. The last county to be created under the Colorado Territory name was San Juan County, created three months before statehood. By the time Colorado became a state on August 1, 1876, it had only 26 counties. In January 1877, Routt and Ouray were formed, followed by Gunnison and Custer counties in March.
County Territory or State Created Superseded History
Taos County Territory of New Mexico 18520109 1852-01-09 18610228 1861-02-28 Originally one of the seven partidos of the Spanish , and later Mexican , province of Santa Fe de Nuevo México . One of the nine original counties created by the Territory of New Mexico in 1852 . Excluded from the new Territory of Colorado in 1861
Great Salt Lake County Territory of Utah 18520303 1852-03-03 18610228 1861-02-28 Created in 1852 , and excluded from the new Territory of Colorado in 1861
Green River County Territory of Utah 18520303 1852-03-03 18610228 1861-02-28 Created in 1852 , but never organized . Dissolved in 1857 , but recreated in 1859 . Excluded from the new Territory of Colorado in 1861 , and the Territory of Wyoming in 1868 . Finally dissolved in 1872
Iron County Territory of Utah 18520303 1852-03-03 18610228 1861-02-28 Created in 1852 , and excluded from the new Territory of Colorado in 1861
Sanpete County Territory of Utah 18520303 1852-03-03 18610228 1861-02-28 Created in 1852 , and excluded from the new Territory of Colorado in 1861
Utah County Territory of Utah 18520303 1852-03-03 18610228 1861-02-28 Created in 1852 , and excluded from the new Territory of Colorado in 1861
Washington County Territory of Utah 18520303 1852-03-03 18610228 1861-02-28 Created in 1852 , and excluded from the new Territory of Colorado in 1861
Arapahoe County Territory of Kansas 18550825 1855-08-25 18610129 1861-01-29 Created in 1855 , but never organized . Reverted to unorganized territory when Kansas joined the Union in 1861
Beaver County Territory of Utah 18560105 1856-01-05 18610228 1861-02-28 Split from Iron and Millard counties in 1856 . Excluded from the new Territory of Colorado in 1861
Broderick County Territory of Kansas 18590207 1859-02-07 18610129 1861-01-29 Split from Arapahoe County in 1859 , but never organized . Reverted to unorganized territory when Kansas joined the Union in 1861
El Paso County Territory of Kansas 18590207 1859-02-07 18610129 1861-01-29 Split from Arapahoe County in 1859 , but never organized . Reverted to unorganized territory when Kansas joined the Union in 1861
Fremont County Territory of Kansas 18590207 1859-02-07 18610129 1861-01-29 Split from Arapahoe County in 1859 , but never organized . Reverted to unorganized territory when Kansas joined the Union in 1861
Montana County Territory of Kansas 18590207 1859-02-07 18610129 1861-01-29 Split from Arapahoe County in 1859 , but never organized . Reverted to unorganized territory when Kansas joined the Union in 1861
Oro County Territory of Kansas 18590207 1859-02-07 18610129 1861-01-29 Split from Arapahoe County in 1859 , but never organized . Reverted to unorganized territory when Kansas joined the Union in 1861
Peketon County Territory of Kansas 18590207 1859-02-07 18610129 1861-01-29 Created in 1859 , but never organized . Reverted to unorganized territory when Kansas joined the Union in 1861
Arrappahoe County Territory of Jefferson 18591128 1859-11-28 18610228 1861-02-28 One of the 12 counties created by the extralegal Territory of Jefferson in 1859
Cheyenne County Territory of Jefferson 18591128 1859-11-28 18610228 1861-02-28 One of the 12 counties created by the extralegal Territory of Jefferson in 1859
El Paso County Territory of Jefferson 18591128 1859-11-28 18610228 1861-02-28 One of the 12 counties created by the extralegal Territory of Jefferson in 1859
Fountain County Territory of Jefferson 18591128 1859-11-28 18610228 1861-02-28 One of the 12 counties created by the extralegal Territory of Jefferson in 1859
Heele County Territory of Jefferson 18591128 1859-11-28 18610228 1861-02-28 One of the 12 counties created by the extralegal Territory of Jefferson in 1859