Dear Ms. Few,
Thank you for posting your request on History Hub!
We suggest that you request a copy of his Official Military Personnel File (OMPF). OMPFs and individual medical reports for officers of the U.S. Army who were separated from the service after June 1917 and prior to 1958 are in the custody of NARA's National Personnel Records Center in St. Louis. In many cases where personnel records were destroyed in the 1973 fire, proof of service can be provided from other records such as morning reports, payrolls, and military orders, and a certificate of military service will be issued. Please complete a GSA Standard Form 180 and mail it to NARA's National Personnel Records Center, (Military Personnel Records), 1 Archives Drive, St. Louis, MO 63138-1002. You can also fax the form to 314-801-9195 OR view the record by visiting the NPRC Archival Research Room in St. Louis, MO. If you do not know the information requested in a given field, you can leave this blank, however the more information you provide, the easier it will be for NARA staff to find responsive records. You can also attach additional information about the soldier, such as a little of units he served. For more information see Official Military Personnel Files (OMPF), Archival Records Requests.
We searched the National Archives Catalog and located the series titled Draft Registration Cards, 1917-1918 in the Records of the Selective Service System (World War I) (Record Group 163) and located a registration card for William Clark Little, born December 2, 1895, which may be a match for your grandfather. His occupation is listed as “Student, R.O.T.C” and in “where employed” there are two words that appear to be “Haverford College” which are scratched out and “Fort Niagara N.Y.” is written above it. For access to and/or copies of these records, please contact the National Archives at Atlanta (RE-AT) via email at firstname.lastname@example.org. The registration card is available in digital form and can be viewed online via Fold3. There may be a fee for using this service. Instead, you may view these records online at one NARA's facilities for free via a NARA PC. For the nearest NARA location, please consult our web page at https://www.archives.gov/locations/. Also, some public and university libraries provide access to Fold3 to their patrons.
We also located Lists of Incoming Passengers, 1917 - 1938 and Lists of Outgoing Passengers, 1917 - 1938 in the Records of the Office of the Quartermaster General (Record Group 92) and located an entry for 2nd Lieutenant William C. Little (Infantry) in E Company, 314th Infantry Regiment, 79th Infantry Division departing July 10, 1918 from Hoboken, New Jersey, on the SS Leviathan. When aslo located a listing for 1st Lieutenant William C.Little departing from June 18, 1919 from Brest, France on the SS Agamemnon. For access to and/or copies of these records, please contact the National Archives at College Park - Textual Reference (RDT2) via email at email@example.com They are also available via Fold3 as the data collection US Army WWI Transport Service, Passenger Lists
In addition, we searched Ancestry.com and located records for him in their data collections Pennsylvania, WWI Veterans Service and Compensation Files and New York, World War I Veterans' Service Data, 1913-1919 that we are also attaching. We are attaching a courtesy copy of these records, because the information about his service may be useful when you are requesting his OMPF.
You also may be interested in the website Log Cabin Memorial - Veterans 314th Infantry Regiment A.E.F that includes numerous sources about the unit during World War I and the memorial of the unit, to include a photograph of the plaque listing Little, W. Clark.
We hope this is helpful. Best of luck with your family research!