Before you start

An SSN or ITIN
Form W-4 with your employer for federal withholding
Ohio Form IT 4 with your employer for state and school district withholding
Your work municipality and your residence municipality, which are frequently different
Your school district number, which determines whether a district income tax applies

Step-by-step

1
Complete the federal W-4 and the Ohio IT 4 on day one
The Ohio IT 4 sets state withholding and is also where you give your school district number, which is what triggers school district income tax withholding if your district levies one. Leaving that field blank does not remove the liability — it just stops it being withheld.
Via employerWho: YouFirst week of employment
2
Identify your work municipality and your residence municipality
They are often different, and both tax you. Your employer withholds for the work city — Columbus's rate is 2.5%. Your residence city taxes your income too and generally credits what you paid the work city, sometimes only in part. Where the credit is partial, or where you live somewhere with a higher rate, the difference is yours to file and pay.
OnlineWho: You
3
Look up your school district income tax
About two hundred Ohio school districts levy an income tax, entirely separate from the municipal one, filed on Ohio Form SD 100. Whether one applies depends on the school district your address sits in, which does not follow city boundaries. Look up the district number for the exact address on the Department of Taxation's finder before you assume it does not apply.
OnlineWho: YouBefore your first payslip
4
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
5
Check for an applicable tax treaty
The US has treaties with around 70 countries that can reduce or exempt tax on particular income. Ohio starts from federal figures, so a federal treaty position generally flows through to the state return. Municipal returns follow their own rules — confirm rather than assuming the treatment carries all the way down.
OnlineWho: You
6
File federal, Ohio, municipal and — if applicable — school district returns
The tax year is the calendar year, due 15 April. Columbus administers its own municipal income tax through the city's Income Tax Division; many suburbs use the Regional Income Tax Agency or the Central Collection Agency instead. That means the filing address depends on which city you live in and which you work in, and it can genuinely be three or four separate returns.
OnlineWho: YouBy 15 April annually
7
If you buy, understand Ohio's property tax reduction factor
Ohio limits how much most voted property tax levies can grow when valuations rise, so a large county reappraisal does not translate one-for-one into a larger bill. It is a genuinely unusual mechanism and it makes headline reappraisal percentages misleading. Check the actual charge on the parcel with the Franklin County Auditor rather than extrapolating from a news figure.
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 — check the municipal and school district boxes
Form 1099s for freelance, interest and investment income
Forms W-4 and Ohio IT 4 filed with your employer
Your school district number for the exact residential address
Passport and travel history for the substantial presence day count
Foreign account statements for FBAR reporting

Things most newcomers don’t know

Ohio taxes municipal income where you work — the opposite of Maryland.

In Maryland the local income tax follows your home. In Ohio it follows your job as well: the work city taxes the income earned there and the residence city taxes you too, with a credit between them that is sometimes partial. Living in Dublin and working in Columbus does not avoid Columbus's 2.5%; it may add Dublin's on top of the credit. Compare job offers on the pair of cities, not on the salary.

Source: Ohio Department of Taxation — municipal income taxes

The school district income tax is the one nobody warns you about.

Around two hundred Ohio school districts levy an income tax of their own, filed separately on Form SD 100, and it is only withheld if your school district number is on the Ohio IT 4 you gave your employer. District boundaries do not follow city boundaries. People discover this as an unexpected bill with interest, years in, which is entirely avoidable by looking up the address once.

Source: Ohio Department of Taxation — school district income tax

Ohio's property tax reduction factor makes reappraisal headlines misleading.

When county valuations jump, Ohio's reduction factor claws back most voted levies so that they raise roughly the same money rather than scaling with values. So a headline about a 40% reappraisal does not mean a 40% tax rise. It also means some levies are, in effect, fixed-revenue. Check the parcel's actual charge with the county auditor rather than reasoning from the percentage.

Source: Ohio Department of Taxation / Franklin County Auditor

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

Assuming a flat 2.75% state rate is the whole picture, and forgetting two municipal layers.
Leaving the school district number blank on the Ohio IT 4 and accruing an unwithheld tax.
Assuming living outside Columbus avoids Columbus tax when you work in the city.
Assuming the residence-city credit is always full. It frequently is not.
Filing with the wrong collection agency — Columbus collects its own, many suburbs use RITA or CCA.
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.