which u.s. state has the highest income tax?
(CNSNews.com) â The Tax Foundation has ranked the states by their state income tax rates and among the highest are California, Hawaii, and Oregon. On a U.S. map, the Tax Foundation shows that the following 10 states (and counting the District of Columbia) have the highest individual income tax rates in 2014: California, 13.3%. Hawaii, 11.0%.