What local city or county income taxes might I owe on top of state tax?

Beyond state income tax, thousands of localities impose their own income or wage taxes, and they're easy to overlook. New York City and Yonkers tax residents directly, Philadelphia levies a wage tax on anyone who works there, and many Ohio, Pennsylvania, Kentucky, and Michigan municipalities have local income taxes collected through payroll. Some are based on where you live, others on where you work, and a few tax both. These usually aren't covered by your state's credit for taxes paid to other states, so cross-border commuting can create real extra cost. Check your pay stub for local withholding and confirm your city and school-district obligations on the local finance department's site, since missing a local return can trigger penalty notices even when your state return is fine.