Baltimore County has one of the strictest shed permit thresholds in Maryland — just 120 square feet, lower than most other counties. That means a standard 10×12 shed sits right on the line, and if your property is in a Historic District, a permit is required no matter how small the structure. This guide covers exactly when a permit is required, the specific building guidelines that apply to all sheds, what documents you need to apply, how the process works, and the special situations — Historic Districts, floodplains, Critical Area, well and septic — that change the rules entirely.