African-Americans were over represented in the Union Army: they constituted less than 1 percent of the population of the North, but made up about 10 percent of Union Army forces in battle. In fact, more than 85 percent of eligible African-Americans in the Northern states enlisted in the Army.

These black soldiers earned significantly less than their white counterparts. Records show that white soldiers were paid $13 a month, while black soldiers earned $10.

Many African-American soldiers refused to accept their pay as a way of protesting the wage discrepancy. Abolitionists within and outside of Congress took up the cause, and in 1864 black soldiers were finally paid the same as white soldiers. The government also paid back pay to these soldiers, back to the day they enlisted in the Union Army.