21st Mississippi Infantry
April 9 Appomattox Court House. Surrendered 4 officers and 44 enlisted men. I am unaware of their source for this info.
http://www.civilwarintheeast.com/CSA/MS/21MS.php
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The Regimental Personnel Listing found at the American Civil War Research Database indicates those who surrendered at Appomattox April 9. It looks like there were many more than the 48 quoted above in their list.
This is a subscription service found at:
http://www.civilwarintheeast.com/CSA/MS/21MS.php
Subscription information at:
http://www.civilwardata.com/demo1.html