When the Civil War began on 12 April 1861, LaSalle County had less than 50,000 residents. However, the people of the county quickly responded to a call for volunteers with 10 percent of its population signing up to join the Union. By the summer of 1862 another call for volunteers was sent out. In September of that year, a report noted that out of 629 men in the city of Peru between the ages of 18 and 45, 163 had volunteered. The war ended on 9 April 1865, with the surrender of General Lee. (Source: History of LaSalle County, Illinois, Volume I, 1886)
The Peru Historical Society is currently performing research to gather information about the people from Peru who served in the Civil War.