This category is managed by the US Civil War Project in association with the Categorization Project. For assistance with this or related categories ask in G2G making sure to tag your question with both categorization and US_Civil_War.
Though formed in the numerical order as the 117th Volunteers Infantry Regiment, it was designated as the 13th Cavalry.
See:
- WikiTree Category 13th Regiment, Pennsylvania Cavalry.
- National Park Service Soldiers and Sailors Database 13th Regiment, Pennsylvania Cavalry (117th Volunteers)