Mine came from Ireland to Virginia, West Virginia. I don't have a Warren - my lines all repeated the same names over and over - William, Samuel, Matthew - Catherine, Elizabeth, Jane, Mary. Doesn't make it easy to find them.
There is some information on Warren P. Alexander who received a pension in 1886 for the Civil War service in the cavalry while living in Indiana. Try looking at familysearch.org its free for the most part or it can tell you where the records might be found.
Leslie Barker Thomas
related through Samuel Alexander + Elizabeth Arbuckle, he was the son of Matthew and Jane Black Alexander.