• Residence-based: Maryland is unique—employers withhold county tax based on where the employee lives, not where they work.
• Piggybacked on state: County income tax is collected with Maryland state income tax. One withholding, one filing.
• Form MW507: Employees indicate their county of residence on Form MW507 for proper withholding.
• Non-residents: Non-Maryland residents working in MD pay a special non-resident tax rate instead of county tax.