This article is from the U.S. Civil War FAQ, by Justin M. Sanders firstname.lastname@example.org with numerous contributions by others.
[Thanks to Geoff Walden and Lynn Berkowitz for updated information.]
First, here are two good reference books that contain much more
information than can be given in this FAQ:
(1) George K. Schweitzer, Civil War Genealogy,
available from: G.K. Schweitzer, 7914 Gleason C-1136,
Knoxville, TN 37919
(2) B.H. Groene, Tracing Your Civil War Ancestor
An additional reference dealing in Confederate records is
James C. Neagles, Confederate Research Sources: A Guide to Archive
Collections (ISBN 0-916489-11-6, Ancestry Publications, P.O. Box
476, Salt Lake City, UT 84110)
The basic facts on your ancestor that you will need to know are his
name, state, regiment, and (if possible) company, for example:
Levi Lindsey Sanders, 6th Texas Cavalry (CSA), Company I.
If you don't know the regiment name, you can often find it in 19th century
county histories for the county your ancestor lived in. Also be careful
with Confederate regiments; they were frequently referred to by the
commander's name when they in fact had a numerical designation, for
example: 2nd Texas Partisan Rangers a.k.a. Stone's Regiment a.k.a.
Chisum's Regiment. There are frequently indexes listing all the soldiers
from a state which were published in the 19th century as well (this is
almost without exception for the Union states, more rare for the
Confederate states). The National Archives has published a Consolidated
Index to Compiled Confederate Service Records on microfilm which is
available in many large historical libraries (the service records
themselves are also frequently on microfilm at the library). A useful
bibliography of regimental and state histories is C.E. Dornbusch,
_Military Bibliography of the Civil War_ (4 vols).
Assuming that you have the above information, you can obtain copies of
your ancestor's service records by writing to the National Archives.
General Reference Branch (NNRG-P)
National Archives and Records Administration
7th and Pennsylvania Ave.
Washington, DC 20408
and request NATF Form 80. Or you may request NATF Form 80 by sending
Give your name, (snail) mailing address, phone number and netid. Whether
you request NATF Form 80 by e-mail or regular mail, you may wish to
request 3 or more copies, especially if you are researching a Union
veteran or multiple veterans.
When you have the forms, fill one out as completely as possible and
check "military service" (Schweitzer recommends that you write in red ink
next to the veteran's name "Please send complete contents of files.") If
your ancestor fought for the Union, he may have a pension file; you may
fill out a second Form 80 and check "pension record" (again Schweitzer
recommends requesting the entire contents of the file). (The National
Archives will not have pension records for Confederate veterans, but some
former Confederate state did give pensions and their archives may have the
records, details can be found in the above references especially Neagles.)
Some weeks later, the Archives will send you a letter indicating what they
have located and how much it will cost to copy it (typically about $10).