Curious about the purpose of a Special Muster Roll (Civil War)

Dear Ms. Baxter,

Thank you for sharing your question with the History Hub.

My understanding is that a “special muster” is one that falls outside of the regular cycle and that it could stem from any number of occurrences like a battle, a troop relocation, an order from a commanding officer, etc. Regarding the specific special muster you referred to, you might find this discussion helpful. It seems that many units experienced special musters on April 10, 1863.

For further information, we recommend that you contact the Textual Reference Branch at the National Archives in Washington, DC (Archives I). Their email address is archives1reference@nara.gov.

Thank you, again, for posting your question, and good luck with your ongoing search!

The Special Musters of  April 1863 were reported to be held for the purpose of ascertaining the "...exact force as present in the field."  This was done so that recruiting and replacements could be accurately applied, and a draft prepared.