The singer sees a mother with her two soldier sons who are bound for battle. She wishes they were not leaving, and tells how she tried to keep them out of the army. The son(s) tell of their hard service, but say not to worry until they are dead!
The singers from whom Cazden et al collected this song generally felt it was a Civil War song. It can, however, be directly linked to "The Crimean War" [Laws J9]. Roud lumps the two, and I'm tempted to do the same -- but Cazden et al consider it separate, and they have heard the actual performances of the Catskills singers.
Still, you'd probably better see both songs. The Ives-New Brunswick version of "The Crimean War," e.g., is described by Cazden et al as being the same as that of "As I Went Down to Port Jervis."
This may mean less than it says, however; the Gardner/Chickering tune of "The Crimean War" is not the same as "Port Jervis" -- but similar; both are 6/8, both follow similar rhythms, both avoid the use of the fourth (causing Cazden et al to show it with no flats even though it's in F -- a confusing bit of notation). The primary difference is that the Cazden versions are true pentatonic; Gardner/Chickering do have one instance of a (major) seventh. - RBW