The advent of the Civil War did not slow white migration into the western
territories.  Mineral strikes and the promise of wealth attracted
thousands to the area of the Colorado and Missouri rivers as well as the
mountains of the Southwest.  This massive influx of people meant renewed
conflict with the Indian nations that had recently settled in the plains. 
Huge numbers of volunteer forces of both the Union and Confederate armies
were called into service.  Shown in this Matthew Brady photograph are Union
Army generals who were prominent during the Indian Wars: (from left to
right) Philip Sheridan, James W. Forsyth, Wesley Merrit, Thomas C. C.
Devin, and George Armstrong Custer.