The bulk of the records relating to individual regiments of the U.S. Army are in the Records of the Adjutant General's Office, 1762 - 1917 (Record Group 94). Some of these major series include:
- Regimental and Company Books of Civil War Volunteer Union Organizations, 1861 - 1867 (State and US Volunteers to include United States Colored Troops)
- Compiled Records Showing Service of Military Units in Volunteer Union Organizations
- Summaries Relating to the History of Various Regular Army Units
- Record of Regiments, 1863 - 1865 [Colored Troops Division]
- Lists of Civil War Volunteer Organizations, ca. 1861 - ca. 1865
- Volunteer Army Registers, 1865 - 1865
- Station Books of Volunteer Regiments, 1861 - 1898
- Index to Civil War Volunteer Army and Corps Organizations, 1861 - 1865
- Duplicate Copies of Muster and Descriptive Rolls of Volunteer Organizations, 1864 - 1865
- Returns of Military Organizations, ca. 1800 - 12/1916
- Official Battle Lists of the Civil War, 1861 - 1865
- Histories of Commands, 1863 - 1863
- Muster Rolls of Volunteer Organizations During the Civil War, Mexican War, Creek War, Cherokee Removal, and Other Wars, 1836 - 1866
- Muster Rolls of Regular Army Organizations, 1784 - 10/31/1912.
National Archives Preliminary Inventory 17: Preliminary Inventory of the Records of the Adjutant General's Office by Lucille H. Pendell and Elizabeth Bethel is available on the Allen County Public Library's Genealogy Center website.
The National Archives also has 724 series related to various regiments in the Records of U.S. Regular Army Mobile Units (Record Group 391) and 290 series in the Records of U.S. Army Continental Commands (Record Group 393).
Records pertaining to Confederate units are in the War Department Collection of Confederate Records (Record Group 109). Some of the series that contain records pertaining to specific units include:
- Record Books of Executive, Legislative, and Judicial Offices of the Confederate Government
- Carded Records Showing Service of Military Units in Confederate Organizations
- Orders Issued by Various Confederate Commands
- Confederate Muster and Pay Rolls
- Confederate Battle Reports.
Depending on the unit, there may be additional information in various other series. Please note that because of the circumstances of the war, not all Confederate records survived the conflict and not all of those that did came into federal custody.
Preliminary Inventory 101: Preliminary Inventory of the War Department Collection of Confederate Records (Record Group 109) by Elizabeth Bethel is available on the Allen County Public Library's Genealogy Center website.
Researchers may email the National Archives at Washington, DC - Textual Reference (RDT1) at firstname.lastname@example.org or post inquiries here at History Hub to request more information about the various records in NARA custody relating to Civil War units. Please be as specific as possible about which units you are researching and what type(s) of information you are seeking.
The Civil War Soldiers and Sailors System (CWSS) is a database containing information about the men who served in the Union and Confederate armies during the Civil War. Other information on the site includes histories of Union and Confederate regiments, links to descriptions of significant battles, and selected lists of prisoner-of-war records and cemetery records, which will be amended over time. The CWSS is a cooperative effort between the National Park Service and several public and private partners whose goal is to increase Americans' understanding of this decisive era in American history by making information about it widely accessible.
For both Union and Confederate volunteer units raised by states, there may be additional information in the custody of the relevant state archives and state libraries. Also, the staff of some Civil War related museums and U.S. state historical societies and museums may be able to assist you with your research.
Many histories have been published about various Civil War units, ranging from books written soon after the war by veterans of the units to works by recent authors. We suggest searching libraries (to include the Library of Congress) retailers, and online sites such as Google Books, the Internet Archive, and HathiTrust. WorldCat and Social Networks and Archival Context can sometimes be used to locate institutions with relevant books and manuscript collections.
For additional resources and research advice, please see:
- Civil War Records: Basic Research Sources from the National Archives,
- The Little Regiment: Civil War Units and Commands (to include the appendices) from NARA’s Prologue Magazine,
- US Civil War: Selected Resources from the Library of Congress,
- Civil War Research and Commemoration from the U.S. Army Center of Military History
- Beginning United States Civil War Research from FamilySearch,
- The Union :a guide to federal archives relating to the Civil War available on HathiTrust
- The Confederacy: a guide to the archives of the Government of the Confederate States of America also available on HathiTrust.