Territorial Evolution of The United States - 1860s

1860s

February 8, 1860

Texas began claiming Greer County, Texas, controlled at that time by the federal government as unorganized territory, and now in present-day Oklahoma.

January 29, 1861

The eastern portion of Kansas Territory was admitted as the 34th state, Kansas. The western portion became unorganized territory until Colorado Territory was created on February 28, 1861.

February 4, 1861

The Confederate States of America (CSA) was formed. The Southern states seceded at different dates and joined the CSA at different dates; to simplify the map, only the final form of the CSA is shown here. There were rebel governments as well as Union governments in Kentucky and Missouri, and the CSA had full control over Indian Territory. To view a detailed animated map depicting the various state secessions see CSA states evolution.

February 28, 1861

Colorado Territory was organized from land taken from New Mexico, Utah, and Nebraska territories and unorganized territory previously part of Kansas Territory. It occupied present-day Colorado. Also, the eastern tip of the Washington Territory was transferred to Nebraska Territory.

March 2, 1861

Dakota Territory was split from Nebraska Territory, and included the unorganized land left over from Minnesota Territory. Dakota Territory consisted of both present-day North and South Dakota, as well as most of Montana and northern Wyoming. Nebraska Territory consisted of all of Nebraska and southeastern Wyoming. Nevada Territory was split from Utah Territory, corresponding to northwestern present-day Nevada; the eastern border was the 39th meridian west of Washington, D.C.

August 1, 1861

The Confederacy established Arizona Territory (CSA) in the southern half of the Union's New Mexico Territory. It would be organized on February 14, 1862. It corresponded to the southern halves of present-day Arizona and New Mexico.

July 14, 1862

Due to its nature as a mining and grazing area, land started to be added to Nevada Territory to accommodate these activities. Its eastern border was moved eastward from the 39th meridian west from Washington, to the 38th meridian west from Washington, transferring the land from Utah Territory.

February 24, 1863

The Union created its own Arizona Territory, splitting it off from New Mexico Territory, making both territories correspond to their present-day states, except for Arizona Territory including the southern tip of present-day Nevada.

March 4, 1863

Idaho Territory was created from portions of Washington, Dakota, and Nebraska Territories, consisting of present-day Idaho, Montana, and most of Wyoming. Nebraska and Washington Territories were left corresponding to their present-day counterparts.

June 20, 1863

The counties of northwestern Virginia (whose population had opposed secession from the Union and established a pro-Union state government) were split off and were admitted as the 35th state, West Virginia. The new state had been mostly under Union control since late 1861, but is not recognized by the Confederate and state governments in Richmond.

May 26, 1864

Montana Territory was split from Idaho Territory, which also had some land transferred to Dakota Territory. Montana Territory corresponded to present-day Montana, Idaho Territory consisted of Idaho and western Wyoming, and Dakota Territory included both North and South Dakota, and most of Wyoming.

October 31, 1864

Nevada Territory was admitted as the 36th state, Nevada; it was a bit smaller than it is today, lacking area in both the east and south.

April 9, 1865

The main army of the Confederate States of America surrendered, and the Confederacy dissolved soon afterward. Much of the Confederate States' territory had already been retaken by force of arms prior to this point and the process of Reconstruction and readmission to the union would take several years following the Confederacy's collapse; to simplify the map, the former Confederate states are shown as already readmitted. To view a detailed animated map depicting the various state readmission during Reconstruction see CSA states evolution.

May 5, 1866

Nevada's eastern border was moved from the 38th meridian west from Washington, to the 37th meridian west from Washington, transferring land to it from Utah Territory.

January 18, 1867

The northwestern corner of Arizona Territory was transferred to the state of Nevada, giving it its present-day borders.

March 1, 1867

Nebraska Territory was admitted as the 37th state, Nebraska.

October 11, 1867

The United States purchased Alaska from Russia; it was designated the Department of Alaska, and corresponds, except for a boundary dispute, to present-day Alaska.

July 25, 1868

Wyoming Territory was formed from portions of Dakota, Idaho, and Utah Territories, corresponding to the present-day borders of Wyoming.