Which form do I file if I was a part-year resident of the District of Columbia?
Use Form D-40 (visit Tax Forms, Publications, and Resources); however, you must prorate your standard deduction or itemized deductions and your personal exemptions.

What if I live in DC and work in Maryland or Virginia?
If you lived in the District of Columbia, you are required to file a DC tax return. However, your employer may not be required to withhold DC taxes.

If I claimed itemized deductions on my federal return, must I also itemize on my DC return?
Yes. If you claim itemized deductions on your federal tax return, you must itemize on your DC tax return. You must take the same type of deduction (itemized or standard) on your DC return as taken on your federal return.

My employer withheld District of Columbia income tax, and I am not a resident of DC. Which form do I file to receive a refund?
Use Form D-40B, Non-Resident Request for Refund (available by visiting Tax Forms, Publications, and Resources).

What filing status should I use on my District of Columbia return if I filed as Head of Household on my federal return?
Use the same filing status that you used on your federal return.

Who should pay estimated taxes?
You must file a Form D-40ES, Declaration of Estimated Tax voucher, if you are required to file a DC individual income tax return and expect to owe $100.00 or more after subtracting your tax withheld and any credits. A D-40ES booklet may be obtained by visiting Tax Forms, Publications, and Resources. If you are filing electronically, you may complete a worksheet of your estimated tax payment at the Electronic Taxpayer Service Center.

How do I amend my DC return after I discover an error?
To file an amended return for the current year, fill in the amended return oval, and complete the tax forms with the corrected information explaining the changes. Do not file an amended return with any other return. If the  Internal Revenue Service adjusts your individual income tax return, you must file an amended DC return within 90 days of receiving notice of the federal change. To amend prior year returns you need to file a copy of your original return along with an amended return using the form for the year being amended. Include an explanation of the changes.