It's all relative man. For me (because I grew up in Alabama) Maryland is a Northern state. With that being said, some places like Westminster and Eldersburg would fit in perfectly anywhere in the South. MoCo is pretty liberal, but as recently as 15-20 years ago Olney used to be the site of Klan rallies.
Gaithersburg in MoCo too. Game Preserve Road had clan meetings in the 1990s.
But I will never recognize Maryland as a Southern state. It sill pisses me off when Virginians say they are from the South.