195
https://www.rockthevote.org/how-to-vote/same-day-voter-registration/
map from: https://www.axios.com/2024/10/31/voter-registration-election-day-2024
Another note that New York is currently even weirder having only allowed same day voter registration on a single day of early voting rather than the entire period unlike North Carolina
Many of states on that map have started adopting it only more recently, so there's been a push to increase it! If it's not in your state, consider writing to your local state legislature representative to push them to pass laws for it next election!
It managed to get through in red Utah in 2018, so don't think it's necessarily a lost cause even if you are in a red state (though yes they are more resistant to it)
As a Nebraskan I can safely say my local state legislature representative would wipe his ass with any such request. Still worth trying, of course.