Nixon and Reagan are tied for the most states. Both won 49.
Reagan came closest to winning every state, as has been said before. That's the sole criteria by which it can be judged the greatest landslide.
He was going to visit Minnesota once and only once. He believed it was bad form to campaign in his opponent’s home state, but the MN GOP begged him to come so he was going to do one appearance.
On the way to this appearance Air Force One had mechanical problems. Reagan eventually relented to the pilots and cancelled his appearance.
If not for that he may have won all 50 states.
In 1916, Charles Hughes was supposed to play golf with the governor of California. He cancelled at the last minute (I don't know why). Hughes ended up losing California by 3773 votes. In those days, the governor could have swung enough votes in Hughes' favor if he had just played g