Sister-in-law passed away in 2018. She lived in Illinois. We live and work in Wisconsin. Her Estate sent us a Illinois Schedule K-1-T. Do we need to file an Illinois Tax Return as well as our normal Wisconsin Tax Return?
Yes, if you received a K-1 for an estate/trust that is from another state, you will need to file a non-resident return for that state (Illinois) and report the Illinois K-1 income only. TurboTax recommends that you complete the non-resident return first so that you may received credit for any taxes due/paid to the non-resident state on your resident (WI) return.
Below is more information about filing a non-resident return: