IIRC, the Maryland legislature wasn’t given a chance to vote on secession. That makes them officially neutral.
I’ll readily admit to being corrected.
My daddy’s people in Kentucky were very confused.
And the county heads in my home county voted against secession because war would interfere with our traditional industry: smuggling. And that’s true to this day.
They were held under house arrest in Fort McHenry and forbidden to vote on secession.
That makes them officially neutral.
If you are neutral with a gun to your head, does that count?
State sentiment was actively Southern, street riots in Baltimore where business people threw rocks and bricks at invading northern militias, railroad bridges burned, and able bodied men leaving home to join up with the Virginia Regiments or the First MD Volunteers (Confederate Artillery unit), all despite the lack of ability of the legislature to act.
The couplet from the State Song "Avenge the patriotic gore/That flecked the streets of Baltimore" refers to the riots: the State Song Maryland My Maryland was written by an expat Marylander during the war while in Louisiana.
While thoroughly occupied by Union forces, the sentiment was still strongly Southern.