Montana in the Civil War
Montana had little role in the Civil War. In 1861, it was divided between the Dakota Territory and the Washington Territory, then in 1863, it became part of the Idaho Territory. The Montana Territory was created on May 26, 1864, three years after the start of the Civil War.
Additional information can be found in the Wikipedia article, Montana in the American Civil War (accessed 15 November 2011).
Montana Military Units
No military units were raised specifically from Montana. However men from Montana did fight in the Civil War.
1890 Census Veterans Schedules - The "Special Schedules of the Eleventh Census (1890) Enumerating Union Veterans and Widows of Union Veterans of the Civil War" (NARA M123) (Family History Library film 338194) are available online for the state of Montana. The schedules list Union veterans and their widows living in Montana in 1890. A published index is also available. For more information on the 1890 Veterans Schedules see Union Census Records.
Compiled Service Records - The Compiled Service Records ($) (Fold3.com) of volunteer Union soldiers who served in organizations from the Territory of Dakota are available online. In the future, these records will be made available at no charge through the National Archives web site. The service records are also available at no charge at National Archives research rooms. The compiled service records consist of an envelope containing card abstracts taken from muster rolls, returns, pay vouchers, and other records. Service records may provide rank, unit, date of enlistment, length of service, age, place of birth, and date of death. For more information see Union Service Records.
Civil War Pension Index Cards - An Index to Pension Applications of veterans who served in the US Army between 1861-1917 is available on FamilySearch. Each card gives the soldier’s name, application and certificate numbers, state of enlistment, and might include rank and death information. The majority of the records are of Civil War veterans, but the collection also includes records for veterans of the Spanish-American War, the Philippine Insurrection, the Indian Wars, and World War I. For more information see Union Pension Records.