Union burial detail at Antietam. Photo taken by Alexander Gardner.
During the Civil War 169 men of the 3rd US Regulars, the "Buffsticks," were called upon to make the ultimate sacrifice in preserving the Union and securing freedom for all. Burial details were a necessary but grim task following a major battle.
The downloadable document linked above contains a list of those Buffsticks lost during the war to battle, illness, accident, or other causes, providing the fallen's name, date and place of death, and burial location when known.
The document was derived almost completely from primary sources--which are provided at the document's end--and include extensive endnotes offering additional details of each soldier's enlistment and other personal details. The document's final pages provide a separate list of the names, company designations, and total number of 3rd US fallen at each Civil War battle in which the Buffsticks participated, as well as overall numbers for the regiment's fallen throughout the conflict.