i.q., idem quod=The same as.
I.R.B. Irish Republican Brotherhood.
Is., Isa. Isaiah.
Is., Isab. Isabella.
I.S.C. Indian Staff Corps.
It. Italian.
I.T. Idaho Territory; Indian Territory.
Jan. January.
Jas. James.
J.C., Juris Consultus=Jurisconsult; Jesus Christ; Justice Clerk.