Until 2022, Mississippi was the only US state which didn’t recognize the Armenian Genocide, a genocide performed by the Ottoman Empire. The Ottoman Empire’s successor state, the Turkish Republic, denies the Armenian Genocide in the modern day.

Idk about those, but you could make a map like this for Martin Luther King Jr. Day. It took until the year 2000 for all 50 states to recognize it as an official holiday. And some states still celebrate Confederate heroes traitors on the same day.