If you work in Maryland but reside in a reciprocal tax state (Pennsylvania, Virginia, West Virginia or Washington, D.C.),and your only income from a Maryland source is wages, you can be exempt from Maryland income tax and Maryland withholding tax on those wages. Follow the instructions for line 4 of the MW507 form.
Ask your employer to withhold PA taxes. Pennsylvania's state income tax rate is a flat 3.07% with no personal exemptions, but virtually no deductions or credits
http://forms.marylandtaxes.com/current_forms/mw507.pdf
