I’m ignoring “alternative facts” here. (I suppose calling them Alt-Fax would be as hip as we can get, given alt-right and Alt-Reich and whatever. Yes, Alt-Fax, because it’s so much easier to type than the, um, alternative. Did you get that? Ha ha? It was accidental.)
Oh dear, I didn’t quite ignore them, did I?
But here’s a credible number from 538’s Significant Digits:
Crowd scientists estimate that at least 470,000 people attended the Women’s March in Washington. D.C. Metro ridership was measured at 1,001,613 entries, the second-biggest daily volume in the history of the D.C. Metro, after only President Obama’s 2009 inauguration day, which saw about 1.1 million entries. [The Washington Post, The New York Times]