Looks like the troop strength was 200-600K on each side. I'm not sure that would have been the largest army in the world. source: https://www.nps.gov/civilwar/

Looks like the troop strength was 200-600K on each side. I'm not sure that would have been the largest army in the world. source: https://www.nps.gov/civilwar/facts.htm#:~:text=In%20July%201861%2C%20the%20two,January%201863%20totaled%20over%20600%2C000 https://www.nps.gov/civilwar/facts.htm#:~:text=In%20July%201....