When Robert Park McLachlan was born on May 25, 1898, his father, William, was 37 and his mother, Lottie, was 32. He had one sister. He entered the military service in Kentucky. He served in the U.S. Army during World War I as a Corporal in Company F, 16th Infantry Regiment, 1st Infantry Division. He was Killed in Action but declared "Missing" on July 18, 1918, at the age of 20 and is memorialized on Tablets of the Missing, Aisne-Marne American Cemetery, Belleau, France. His name is inscribed on the Buzancy monument as CPL R S MC LACHLIN.