Frederick County's location puts thousands of residents within commuting distance of Washington DC, Northern Virginia, and other Maryland jurisdictions. That creates multi-state tax situations that national software routinely gets wrong — costing taxpayers money in missed credits, duplicate taxes, and filing errors.
Frederick County sits at a geographic crossroads. Residents commute to Washington DC, Montgomery County, Howard County, and Northern Virginia in large numbers. At the same time, workers from DC, Virginia, and Pennsylvania commute into Frederick County for work. Business owners operate across state lines. Remote workers split their time between Maryland and other states.
Each of these situations creates a distinct multi-state tax filing obligation — and each state has its own rules for how to handle it. The Maryland-DC reciprocity agreement, nonresident filing requirements, and multi-state business apportionment rules are areas where we see frequent errors in returns prepared by national software or out-of-state preparers. For a full overview of Maryland's tax obligations, see our Maryland Tax Guide.
Maryland and Washington DC have a tax reciprocity agreement — one of the most important and most misunderstood provisions in Maryland tax law for Frederick County residents.
Under the Maryland-DC reciprocity agreement, a Maryland resident who works in Washington DC owes income tax only to Maryland — not to DC. The agreement means you do not owe DC income tax simply because your employer is located in the District.
This is a significant benefit. Without the agreement, you would potentially owe income tax to both Maryland and DC on the same wages, with only a partial credit to offset the double taxation. The reciprocity agreement eliminates that overlap for most W-2 employees.
The reciprocity exemption is not automatic — it requires action on your part. To prevent DC from withholding income tax from your paycheck, you must file DC Form D-4A (Certificate of Non-Residence in the District of Columbia) with your DC employer. Once filed, your employer stops withholding DC income tax and withholds Maryland income tax instead.
Many Maryland residents who work in DC have never filed Form D-4A — which means DC income tax has been withheld from every paycheck. In this situation you must file a DC nonresident return (Form D-40B) to claim a refund of the DC tax withheld, and a Maryland resident return to pay the Maryland tax owed. We handle this situation regularly for new clients — often recovering multiple years of DC refunds.
The Maryland-DC reciprocity agreement covers W-2 wages only. It does not cover:
If you have any of these types of DC-source income in addition to W-2 wages, you may still need to file a DC nonresident return even if you have filed Form D-4A for your wages.
Maryland and Virginia also have a reciprocity agreement covering W-2 wages. A Maryland resident working for a Virginia employer owes income tax only to Maryland — not to Virginia — on those wages. The process is the same: file Virginia Form VA-4 (Employee's Withholding Exemption Certificate) claiming the reciprocity exemption with your Virginia employer.
Without the Virginia form on file, your Virginia employer withholds Virginia income tax. You would then need to file a Virginia nonresident return to claim a refund while also paying Maryland on the same income.
Maryland has reciprocity agreements with: Washington DC, Virginia, West Virginia, and Pennsylvania. Maryland residents working in any of these jurisdictions owe income tax only to Maryland on their W-2 wages. Each state has its own exemption certificate form that must be filed with the employer to stop withholding.
The flip side: individuals who live outside Maryland but earn income in the state must file a Maryland nonresident return (Form 505). This applies to:
Nonresidents are taxed on Maryland-source income at the Maryland nonresident rate — currently 8.0% — and are not subject to the local county income tax that Maryland residents pay. They file Form 505 rather than the resident Form 502.
Remote work has created a new class of multi-state tax situations that didn't exist at scale before 2020. The key questions for Frederick County remote workers:
If you live in Maryland and work remotely for an employer headquartered in another state, you generally owe Maryland income tax on all your wages — because you are performing the work in Maryland. Most states follow the "physical presence" rule, meaning the tax follows where the work is performed, not where the employer is located.
However, some states — notably New York — follow a "convenience of the employer" rule, which taxes employees on wages regardless of where the work is performed if the remote arrangement is for the employee's convenience rather than the employer's necessity. If your employer is in New York, you may owe New York tax even if you work entirely from your Frederick County home.
If your work requires you to physically work in multiple states — for example, you work three days in Maryland and two days in DC each week — you may owe income tax to both states on a pro-rated basis. The reciprocity agreement covers W-2 wages for Maryland-DC workers, but if you are splitting time between Maryland and a non-reciprocity state, apportionment becomes necessary.
Many employers withhold income tax based on the state where the employee's paycheck is processed or where the office is located — not necessarily where the work is performed. This means your W-2 may show withholding for a state where you owe little or no tax, while showing no withholding for Maryland where you owe significant tax. We review W-2 withholding for all multi-state clients and adjust estimated payments accordingly.
Business owners who operate in multiple states face a different set of challenges. If your business has nexus — a sufficient connection — in more than one state, you may have income tax filing obligations in each of those states.
Maryland uses a single-sales-factor apportionment formula for most businesses — meaning the percentage of business income taxable in Maryland is based on the ratio of Maryland sales to total sales everywhere. If 40% of your business's sales are to Maryland customers, 40% of your income is apportioned to Maryland for tax purposes.
This is more favorable than older three-factor formulas that also weighted payroll and property in the apportionment calculation. A business with significant Maryland employees and equipment but mostly out-of-state customers can now apportion a smaller share of income to Maryland than under the old formula. Our tax planning team reviews apportionment calculations for all multi-state business clients.
| Situation | Returns Required | Key Action |
|---|---|---|
| MD resident, W-2 job in DC | Maryland resident return only | File DC Form D-4A with employer |
| MD resident, W-2 job in DC, DC tax withheld | Maryland resident + DC nonresident (D-40B) | File DC return to claim refund |
| MD resident, W-2 job in Virginia | Maryland resident return only | File Virginia Form VA-4 with employer |
| MD resident, remote work for out-of-state employer | Maryland resident return; possibly other state | Confirm withholding matches MD obligation |
| VA/DC/PA resident, W-2 job in MD | Home state return only (reciprocity) | File MD reciprocity exemption with employer |
| Non-reciprocity state resident working in MD | MD nonresident (505) + home state return | Claim credit in home state for MD tax |
| MD resident with rental property in DC | Maryland resident + DC nonresident | Report DC rental income on both returns |
You will file a part-year resident return for both Maryland and DC for the year of the move. Maryland uses Form 502 with a part-year designation; DC uses Form D-40. Each return covers only the income earned while you were a resident of that jurisdiction. If you continued working in DC after moving to Maryland, you will also need to address the withholding situation going forward and file Form D-4A with your employer.
You file a joint Maryland resident return reporting both spouses' income. Your spouse's DC wages are included on the Maryland return as Maryland-taxable income (since you are Maryland residents). Your spouse should file Form D-4A with their DC employer to stop DC withholding. If DC tax was withheld, you file a joint DC nonresident return (D-40B) to claim a refund.
Yes. Federal government employees who are Maryland residents and work in DC are covered by the Maryland-DC reciprocity agreement. File Form D-4A with your federal agency's payroll office to ensure Maryland income tax is withheld rather than DC income tax. Federal civilian pay is subject to the same reciprocity rules as private sector wages.
It depends on whether your business has nexus in those states. Having customers in a state does not automatically create income tax nexus. However, if you have employees working in DC or Virginia, own property there, or exceed economic nexus thresholds, you may have filing obligations. We review nexus for all multi-state business clients as part of our annual engagement.
Roy Cogliandolo, CPA
Mercer Flanagan · Frederick, MD · Updated June 2026
Multi-state returns are one of our specialties. We get the reciprocity forms right, recover missed DC refunds, and make sure you're not paying tax to the wrong state.
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