One of my great-grandfathers was in the U.S. Army at that time, but he never left the USA. I wrote about what I've learned of his experience in post-224 ("My Great-Grandfather's Piece of World War I"). He was at Camp Devens, MA. Here is a picture of one of the companies garrisoned (not his) at Camp Devens in 1918:
Within two years of the armistice, Earle Hazen was married and within three years, my grandmother was born.