I answered "Union" since the relatives closest to me were from Ohio, Iowa, and a few in Indiana and Pennsylvania. On the other hand, I do have some distant ancestors, like cousins several times removed, who fought for the CSA in states like Alabama and possibly the Carolinas.
I had ancestors who fought in most early American wars, from King Philip's/Metacom's War through the AWI, 1812, etc. ... Civil War not so many, but a few. Three of my four late grandparents were in WWII.
Like a number of other posters, most of my direct lineal ancestors on my paternal and maternal sides came to the United States in 1903 and 1907. My late maternal grandmother did not arrive until 1946, and only became a U.S. citizen by 1976.