The Northern Scum

I hear the distant thunder-hum, Maryland!
The Old Line bugle, fife, and drum, Maryland!
She is not dead, nor deaf, nor dumb-
Huzza! She spurns the Northern scum!
She breathes! She burns! She'll come! She'll come!
Maryland! My Maryland!

It would seem that Maryland has decided to secede from the South and join the "Northern scum", as lawmakers recently petitioned to move from the Southern Region of the Council of State Governments to the Eastern Region.

Am I the only one surprised to learn that Maryland was ever considered a "Southern" state to begin with?