Of no importance except that one gets a day off-

Columbus Day is a statuary holiday for U.S. government employees but is not one in all of the states.
Alaska, Arkansas, California, Delaware, Hawai'i, Iowa, Kansas, Kentucky, Louisiana, Michigan, Minnesota, Mississippi, Montana, Nevada, North Carolina, North Dakota, Oregon, South Carolina, Tennessee, Texas, Washington do not observe it.

Alabama, Virginia, Texas, Virginia, Mississippi and other southern states have holidays recognizing Jefferson Davis, Generals Lee and Jackson, Confederate Veterans, etc., and Hawai'i has Kamehameha and Kuhio holidays, etc.

South Dakota recognizes Native American Day on the second Mon. in October.