As for one vote per district, the closest contest was in Illinois, where Kennedy won by some 9000 votes. It was the most hotly contested (think FL, or Ohio more recently), but the truth is that either way, Kennedy had the electoral vote wrapped up with 303 electoral votes to Nixon's 219.
The total popular vote difference was only about 112,000 votes, but those are not what elects the president, electoral votes do. Wikipedia, some information contested in the article
The popular vote spread can be thinned by overwhelming votes for a candidate in one jurisdiction (where they won) and overwhelming votes for their opponent in another (where their opponent won), without changing the electoral vote, so averaging the vote out over all districts can be misleading.
Thanks for all that information. After 2000, I know we all got a good, close-up look at the Electoral College.
I appreciate the work you put into your post - I’ll take a look at the link later on.