This is a list of Civil War regiments from Maryland which fought in the Union Army. The list of Maryland Confederate Civil War units is shown separately.
Infantry
- 1st Regiment Maryland Volunteer Infantry
- 1st Maryland Infantry, Potomac Home Brigade
- 1st Regiment Eastern Shore Maryland Volunteer Infantry
- 2nd Regiment Maryland Volunteer Infantry
- 2nd Regiment Maryland Eastern Shore Infantry
- 2nd Maryland Infantry, Potomac Home Brigade
- 3rd Regiment Maryland Volunteer Infantry
- 3rd Maryland Infantry, Potomac Home Brigade
- 4th Regiment Maryland Volunteer Infantry
- 4th Regiment Potomac Home Brigade Infantry
- 5th Regiment Maryland Volunteer Infantry
- 6th Regiment Maryland Volunteer Infantry
- 7th Regiment Maryland Volunteer Infantry
- 8th Regiment Maryland Volunteer Infantry
- 9th Regiment Maryland Volunteer Infantry
- 10th Regiment Maryland Volunteer Infantry
- 11th Regiment Maryland Volunteer Infantry
- 12th Regiment Maryland Volunteer Infantry
- 13th Regiment Maryland Volunteer Infantry
- 19th Regiment Maryland Volunteer Infantry
- Purnell Legion Infantry
- Baltimore Light Guard Infantry
- Patapsco Guard
Litton's regiment of Maryland infantry
Cavalry
- 1st Regiment Maryland Volunteer Cavalry
- 2nd Regiment Maryland Volunteer Cavalry
- 3rd Regiment Maryland Volunteer Cavalry - Bradford Dragoons
- 1st Regiment Potomac Home Brigade - Cole's
- Purnell Legion Maryland Volunteer Cavalry
- Smith's Independent Company Maryland Volunteer Cavalry
Artillery
- 1st Regiment Maryland Heavy Artillery
- Battery A, Maryland Light Artillery [Rigby's Battery]
- Battery "A" Junior Maryland Light Artillery
- Snow's Battery "B" Maryland Light Artillery
- Battery "B" Junior Maryland Light Artillery
- Battery "D" Maryland Light Artillery
- Baltimore Independent Battery Light Artillery