Hello David, Quite a few years ago, a man by the name of Waldo Rosebush wrote a letter to my aunt ( a DeRosier) and claimed he was descended from DeRosiers. I understand he wrote a book and that a copy of it is in the Library of Congress. Would you happen to know how I could get hold of a copy from there?
My mother was a DeRosier, and I am presently working on her side of the family tree. I have gotten as far back as my gg grandparents, who were Francis A. DeRosier, b. Canada about 1806 or 1807. He married Delia Cassiday, also b. Canada. At some point they moved to St. Lawrence County, NY and stayed there until the early 1840s when they moved to Oswego County where Francis died in 1850 at the age of 44. They had 10 living children at that point, including 2 year old twins. I do not know the names of his parents or siblings, although I think he may have had a brother named Stephen.
If you think we may be on to the same family, please contact me. Thanks