Before you start

An SSN or ITIN
Form W-4 with your employer for federal withholding
Maryland Form MW507 with your employer for state and local withholding
Your county of residence as at 31 December, which sets the local rate
Records of foreign income and foreign financial accounts

Step-by-step

1
Complete the federal W-4 and the Maryland MW507 on day one
The MW507 is where you declare your county of residence, and that declaration is what sets your local income tax withholding. Getting it wrong means either a shortfall in April or over-withholding all year.
Via employerWho: YouFirst week of employment
2
Establish which jurisdiction you live in
Baltimore City is an independent city and sets its own local income tax rate, at the state's maximum. Baltimore County, Howard, Anne Arundel and Harford each set their own, and they differ. Your rate follows your residence on 31 December — not your employer's address, and not your postal town.
OnlineWho: You
3
Determine your US tax residency
The substantial presence test counts weighted days across three years to decide whether the US taxes your worldwide income or only US-source income. Your visa category does not decide this.
OnlineWho: You
4
Check for an applicable tax treaty
The US has treaties with around 70 countries that can reduce or exempt tax on particular income. Maryland starts from federal figures, so a federal treaty position generally flows through to the state return and to the local tax computed on it — but confirm rather than assuming.
OnlineWho: You
5
If you commute across a state line, check the reciprocity
Maryland has reciprocal agreements with several neighbouring jurisdictions including the District of Columbia, Pennsylvania, Virginia and West Virginia, under which residents of one are not taxed by the other on wages. Given how many people here work in Washington, this is a live issue rather than a theoretical one — get the right non-residence form filed with your employer.
Via employerWho: You
6
File federal and Maryland returns by the annual deadline
The tax year is the calendar year and the deadline is normally 15 April. The Maryland return computes state and local tax together, so there is no separate city filing — unlike Ohio or Michigan, Baltimore does not run its own income tax office.
OnlineWho: YouBy 15 April annually
7
If you buy, check the property tax rate and the Homestead cap
Baltimore City's property tax rate is roughly double the surrounding counties', which is the single biggest recurring cost difference between a city rowhouse and an equivalent county house. Maryland's Homestead Tax Credit caps how fast the taxable assessment on an owner-occupied home can rise — but you must have the application on file. Check the credit status on the SDAT record before closing.
OnlineWho: You
8
File an FBAR if foreign accounts exceed $10,000
Aggregate foreign account balances over $10,000 at any point in the year trigger a FinCEN filing, separate from your tax return and with its own penalties.
OnlineWho: You

Documents you’ll need

Form W-2 from each employer, issued by 31 January
Form 1099s for freelance, interest and investment income
Forms W-4 and MW507 filed with your employer
Passport and travel history for the substantial presence day count
Foreign account statements for FBAR reporting

Things most newcomers don’t know

The local income tax follows your home, not your job — the opposite of Ohio.

Maryland's local income tax is levied by the jurisdiction you live in, and collected through the state return. Living in Baltimore City and working in Columbia means you pay the city's rate, which is the state maximum. Living in Howard County and working downtown means you pay Howard's. Anyone comparing two job offers across the region needs to compare addresses, not employers.

Source: Comptroller of Maryland

Baltimore City's property tax rate is roughly twice the neighbouring counties'.

It is the structural reason a rowhouse in the city can look cheap on the sticker and cost more to hold than a larger house in Baltimore County. Renters pay it too, through the rent. It is also the reason the city's tax debate is permanent — proposals to cut the rate come round every few years. Check the current rate for the specific parcel rather than a citywide figure.

Source: Baltimore City / Maryland Department of Assessments and Taxation

The Homestead Tax Credit is applied for, not granted.

Maryland caps the annual increase in the taxable assessment of an owner-occupied principal residence — but only for owners with an approved Homestead application on file, and it does not transfer automatically to a new owner. Buyers who assume it comes with the deed can face a sharp jump at the next assessment.

Source: Maryland Department of Assessments and Taxation

Your visa does not determine your tax residency.

The substantial presence test — a weighted day count across three years — decides whether the US taxes your worldwide income. Someone on a temporary visa can be a US tax resident; someone on a long visa can fail the test. Do the count rather than assuming.

Source: IRS — substantial presence test

Common mistakes to avoid

Comparing a Baltimore salary to another city's without subtracting the local income tax.
Declaring the wrong county on the MW507 and under-withholding all year.
Assuming a 'Baltimore' postal address means the city's local rate applies when it does not, or vice versa.
Buying a city rowhouse without checking the parcel's actual property tax bill.
Failing to file the Homestead Tax Credit application after buying.
Missing the FBAR because a home-country account did not feel 'foreign'.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.