Dear Ms. Goodwine,
Thank you for posting your request on History Hub!
We searched the National Archives Catalog and located 4 digitized files Shankland, John H - Unassigned Veteran Reserve Corps; Shankland, John H - Unit: 7th Infantry, Company: I - Enlistment Rank: Sgt, Discharge Rank: Sgt; Shankland, John H - Unit: 92nd Infantry; and Shankland, John H - Unit: 7th Infantry (3 Months, 1861), Company: I - Enlistment Rank: Pvt, Discharge Rank: Pvt from the series Carded Records of Soldiers Who Served in Volunteer Organizations During the Civil War in the Records of the Adjutant General’s Office (Record Group 94) that are available for you to review.
We also located a series titled Registers of Federal Prisoners of War Confined at Andersonville Prison, Georgia in the Records of the Commissary General of Prisoners (Record Group 249) that was microfilmed as National Archives Microfilm Publication No. M1303. Since M1303 has not been digitized, you may access the descriptive pamphlet and a list of National Archives facilities that have the microfilm using the Microfilm Catalog.
Using Ancestry, we located All Military Results for John Harvey Shankland; Pension File for John H. Shankland - 7th Illinois Infantry (spouse Mary Shankland); and Pension File for John H. Shankland - 92nd Ohio Infantry (spouse Ella Shankland). There may be a fee for using Ancestry. 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 of the images from Ancestry are available for free on Family Search at https://www.familysearch.org/en/.
We hope this is helpful. Best of luck with your family research!