Peter Conover Hains the only Civil War vet who fought in WW1

== Early life ==
Peter was born in 1840 and got into United States Military Academy and was apart of the class of 1861 along with later first lieutenant Alonzo Cushing, George Custer, and later CSA general Young Pierce.
== Civil War-WW1 ==
In 1862 he help fight in the Battle of Hanover Court House which got him the Brevet promotion, on March 3, of 1863 he was moved to the Corps of engineers and fought at the Siege of Vicksburg. He later returned the regular army and in the 1870's designed the U.S. Lighthouse Board, St Augustine lighthouses, and in the 1890s help get the Panama canal building process started. He later fought in the Spanish-American War and was promoted to brigadier general and retired in 1904. He had two sons Peter the second and Thornton, Peter was later convicted of killing his wife's lover and Thornton became a famous novelist. In 1917 he went back into duty during the First World War and was the oldest general in active duty since John E. Wool, he later died at Walter Redd Hospital in 1921.https://en.wikipedia.org/wiki/Peter_Conover_Hains