It depends.
At the beginning of the War of Northern Agression, Maryland was set to secede, but a number of pro South supporters in the state government were jailed. Lincoln was VERY concerned about Maryland, as that would have surrounded the capital.
Back in the 1960s and 70s, if you went to Southern Maryland and listened to the accents, you would swear you were in North Carolina. The Eastern Shore was very southern back then too. Western Maryland leaned strongly to the North, even in the 1860s.
Many folks don't know that slavery was still legal in the border states, even after Lincoln's Emancipation Proclamation. It was legal in areas of the southern states that were under Union control as well, like Northern Virginia outside of DC. Few folks are aware that Delaware was a slave state as well.
I have Marylanders in my family tree, including a Confederate general, and I lived there for a while. Even had a music teacher in elementary school that taught us to sing "Dixie".
I've eaten grits and hashbrowns both, just not during the same meal.
It's definitely a border state, but becoming more and more Yankeeifed every day, just like Northern Virginia.