@jonhai --
I apologize for being a nitpicker, but as a resident of Indiana you definitely are a non-resident of Maryland.
The issue is that Maryland taxes non-residents only on Maryland-source income.
Work income is "sourced" where the work is actually (physically) performed. (There are a few exceptions but they are not relevant to your case.)
Since your work is actually performed in Indiana, your income from that work is Indiana-source income, and therefore not subject to Maryland state income tax.
Think of this example: Coca-Cola is headquartered in Atlanta, Georgia. But that doesn't mean that all Coca-Cola employees across the country pay Georgia state income tax. The only Coca-Cola employees who pay Georgia income tax are those who live in or physically work in Georgia.
**Answers are correct to the best of my ability but do not constitute tax or legal advice.
