Civil War Song Must Learns

Hello.  I am a music teacher.  I am looking at getting a class set of cardboard dulcimers and teaching songs focused around US History for next school year.  As I am new to the mountain dulcimer and its repetoire, I was hoping I could get some suggestions for Civil War songs that would be good for 5th and 6th grade students.  I would be teaching them noter style playing at first and probably using a DAA tuning on diatonic dulcimers.