The Libertarian Party (L.P.) started 2016 with around 411,000 registered voters. After a year of Trump and Clinton and the Libertarian's Johnson/Weld campaign with its record over 4 million votes for the L.P., nearly 100,000 other voters have seen wisdom in registering Libertarian.
According to ballot access maven Richard Winger at Ballot Access News, the Libertarians are now the first nationally-organized Party in American history besides the Republicans and Democrats to break a half-million registered voters.
The L.P. had never broken 400,000 registered voters before this year.
The "nationally organized" part is key, as the California-only American Independent Party has around 507,000. It is well-understood, though, that a vast majority of people registering with it are doing so under the mistaken belief they are merely registering independent of any Party, not joining a specific party with that name. (That Party nominated Trump this year.)
Another sign of increased health for the L.P. is a yearly monetary take for the national Party of likely near $3 million, for what should be their highest-dollar year since 2000.
And another: the L.P. got its most votes ever for U.S. House candidates, 1.67 million, even though it ran the same number of such candidates as in 2014, 122. That's a 73 percent increase in House votes over 2014, with same number of candidates run. (Voter turnout this year was about 58 percent higher than in 2014.)
That's fewer than half the number of federal House candidates the L.P. ran in 2000, the last year in which their House vote total was close to, but not matching, this year's, with a total of 1.61 million. Thus, the Party's votes per candidate have gone up enormously.
For some in-the-weeds discussion of how this year's results on the state level improved the Party's ballot access or "official Party" status, see the Libertarian Party's own blog and Richard Winger's Ballot Access News.