I can't believe the pain involved in claiming state tax exemptions for dividends of federal origin! If you hold mutual funds thru a broker you probably get few if any notices for this info, and you'd be surprised which funds have these with even stock funds having dipped into federal bonds for defensive reasons recently.
Here is what I do... if there some high school student who wants an idea to start a dot-com, please automate the following for a few hundred most popular funds. First find a fund family web site and flounder around for an hour or so. They won't have exemption info anywhere in the dividend area or your fund area. Finally you may find some pdf in an odd place in a goofy, annoying format without ticker names or anything. Note how you have to do work to relate the info to your state.
Then I seem to have trouble getting the info into tax software, where they don't seem to welcome it, and won't properly confirm whether it has been accepted in the 2 ways I tried to enter. Dear H.S. student, please also negotiate a portal from your site to tax software site...