Dear Ms. Randolph,
Thank you for posting your request on History Hub!
We searched the National Park Service’s Civil War Soldiers and Sailors System (CWSS) and located multiple soldiers named William Pitt who served in the Union Army. Of these soldiers, the one that best matches the information you provided is Pitt, William T. of the 1st Regiment, United States Colored Cavalry. As you can see from the linked history, the regiment was formed in Union-occupied Tidewater Virginia not far from Nansemond County, Virginia, and was mustered out in Texas. His service with a African American unit would also be consistent with the history of the Grove Baptist Church that we located on your website. The one discrepancy is the date, as the regiment was active from 1863 through 1866. We presume that your reference to him being discharged in 1861 is a typo.
We then searched the National Archives Catalog and located the series Carded Records Showing Military Service of Soldiers Who Fought in Volunteer Organizations During the American Civil War in the Records of the Adjutant General's Office, 1762 - 1917 (Record Group 94). This series contains a record for William Thomas Pitt of the 1st Colored Cavalry which has been digitized and can be viewed online through the Catalog.
We also located Case Files of Approved Pension Applications of Widows and Other Dependents of the Army and Navy Who Served Mainly in the Civil War and the War With Spain, 1861 - 1934 in the Records of the Department of Veterans Affairs (Record Group 15). This series includes the digitized Approved Pension File for Lillian Pitt, Widow of First Sergeant William Thomas Pitt, Company K, 1st U.S. Colored Troops Cavalry Regiment (WC-439090) which can also be viewed online through the Catalog. This file also contains documentation regarding William Pitt’s application for a disability pension which was later combined with the file for his widow. The pension file is of particular interest because it contains information about Mr. and Mrs. Pitt not found in the service records.
In regards to your specific request for discharge papers, the War Department did not retain a copy of the discharge certificates given to soldiers. While pension files sometimes contain copies of these certificates submitted in support of claims, the majority of pension files do not. Information regarding his William Pitt’s discharge can be found in the service record linked above.
Finally, it may interest you and the members of your church to know that the pension file was scanned through National Archive’s Innovation Hub, which allows members of the public to contribute to making these records available online through Citizen Scanning projects. Those that can not visit our location in Washington DC can also contribute through our Citizen Archivist transcription program.
We hope this information is helpful. Best of luck with your research!