If I live in Ohio, and work in Indiana, why do I have to pay county tax in Indiana?

[Rick19744 · Accepted solution]

Well, it is because that is the law.  The various county taxes are used for a number of governmental services and one of those are the roads.  So county taxes fund repairs and maintenance of county roads which nonresidents use as they commute to and from their place of business.
See the attached from Indiana:
https://www.in.gov/dor/files/dn01.pdf

[Hal_Al]

Ohio has a reciprocal agreement, on wages, with all neighboring states. No Indiana state taxes are withheld or due and you do not need to file an IN return. But OH will tax you on your IN income.
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However the reciprocity agreement does not apply to local city or county taxes. You are not entitled to a refund of the county withholding (box19 on your W-2), unless there was an error in the amount.