It could be early if the Republicans do a bit better than the polls.  Most of the close races are in the Eastern Time Zone, the Central, or both (Kentucky).  Colorado is Mountain Time, but that state is having its first all-mail election.  (Not to be confused with an all-male election, banned in 1920.)  The drop-off deadline for those who didn't mail in their ballots is 7 p.m. MST.

However, if it does come down to the wire, Alaska is very late, and Louisiana and Georgia will have runoffs if no candidate gets a majority.  Conceivably, the 114th Congress might convene with an empty seat from Georgia, which holds its runoff three days later.  Who is the majority if there are 50 Republicans and 49 Democrats?  The Republicans.  His Superfluous Majesty (as Ben Franklin called the Veep) only gets a vote if they are equally divided.  But it could be a very short-lived majority if the Democrat then wins the runoff.

Oh, and Silver's story also has a cool photo of someone who likes Ike voting by machine 62 years ago.