illinois state taxes of out of state capital gains

I currently live in Illinois and recently sold a property in Washington. This property was not my primary residence and was purchased when I lived in Iowa. Do I need to pay Illinois capital gains tax on the property sold if sold in Washington state.

posted

yes because you're a resident (domiciled) in Illinois. just like federal law which taxes US citizens and the equivalent on worldwide income so too do states in which you're domiciled (have a permanent residence) that have an income tax. you should be glad that Washington state has no income tax.