Col. James P. McMahon and group at headquarters of 164th N.Y. Inf.

Chicago citation style
War Department. Office of the Chief Signal Officer. (8/1/1866 - 9/18/1947). Col. James P. McMahon and group at headquarters of 164th N.Y. Inf.. 1860-01-01/1865-12-31. Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/524678. (Accessed June 20, 2018.)
APA citation style
War Department. Office of the Chief Signal Officer. (8/1/1866 - 9/18/1947), (1860-01-01/1865-12-31) Col. James P. McMahon and group at headquarters of 164th N.Y. Inf.. Retrieved from the Digital Public Library of America, http://catalog.archives.gov/id/524678
MLA citation style
War Department. Office of the Chief Signal Officer. (8/1/1866 - 9/18/1947). Retrieved from the Digital Public Library of America <http://catalog.archives.gov/id/524678>.
Note: These citations are programmatically generated and may be incomplete.