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

The Northwest, US Army Department Sep 6, 1862 - Apr 9, 1865

The Sioux Indian War, Aug 12, 1862 - Aug 12, 1864
US Dept. of The Northwest created Wisconsin transferred from Dept. of the Ohio Minnesota and Iowa transferred from Dept. of the Mississipppi Nebraska and Dakota transferred from Dept. of Kansas, Sep 6, 1862
John Pope Commander, Sep 6, 1862 - Nov 28, 1862
Wood Lake, battle, Sep 23, 1862
Nebraska transferred from US Dept. of the Northwest to Dept. of The Missouri Colorado included in Dept. of the Missouri, Oct 11, 1862
Washington L. Elliott Temp Commander, Nov 28, 1862 - Feb 13, 1863

John Pope Commander, Feb 13, 1863 - Jan 30, 1865
Dead Buffalo Lake, action, Jun 26, 1863
Stony Lake, action, Jun 28, 1863
Big Mound, battle, Jul 24, 1863 - Jul 25, 1863
Whitestone Hill, battle, Sep 3, 1863 - Sep 5, 1863

Killdeer Mountain, battle, Jul 28, 1864 - Jul 29, 1864

US Division of THE MISSOURI created including Depts. Of The Missouri and Dept. of the Northwest, Jan 30, 1865
Samuel R. Curtiss Commander, Jan 30, 1865 - Apr 9, 1865
Montana and Western Dakota transferred from US Dept. of The Northwest to Dept. of the Missouri, Feb 17, 1865