World History Maps Interactive Historical Atlas of the Civil War, detail page for:

The West, US Army Department before Nov 6, 1860 - Jul 3, 1861
Western, US Army Department Jul 3, 1861 - Nov 6, 1861

William S. Harney Commander, Nov 10, 1860 - Apr 23, 1861

Nathaniel Lyon Temp Commander, Apr 23, 1861 - Apr 29, 1861
Edmund B. Alexander Temp Commander, Apr 29, 1861 - May 11, 1861
William S. Harney Commander, May 11, 1861 - May 31, 1861
Nathaniel Lyon Commander, May 31, 1861 - Jul 25, 1861
Operations to Control Missouri, Jun 5, 1861 - Dec 31, 1861
Missouri transferred fro US Dept. of the West to Dept. of The Ohio, Jun 6, 1861
US Dept. of the West reorganized as Western Dept. including Iowa Minnesota Kansas Nebraska Colorado and Dakota Missouri and Illinois transferred from Dept. of the Ohio Dept. of New Mexico discontinued and absorbed, Jul 3, 1861
Carthage, engagement near, Jul 5, 1861
John C. Fremont Commander, Jul 25, 1861 - Oct 24, 1861
Wilsons Creek, battle, Aug 10, 1861
Dry Wood Creek, battle, Sep 2, 1861
Lexington, siege, Sep 13, 1861 - Sep 20, 1861
Liberty, battle, Sep 17, 1861
Lexington, battle, Sep 20, 1861
David Hunter Commander, Oct 24, 1861 - Nov 9, 1861
US Dept. of New Mexico recreated New Mexico transferred from Western Dept., Nov 9, 1861
US Dept. of Kansas created Kansas Nebraska Colorado and Dakota transferred from Western Dept., Nov 9, 1861
US Dept. of The Missouri created Minnesota Missouri Illinois and Iowa transferred from the Western Dept. Wisconsin included Western Kentucky transferred from Dept. of the Cumberland, Nov 9, 1861
US Western Dept. discontinued, Nov 9, 1861