I’m guessing 300-350.
I walked around most of the area after most of the crowd had assembled on the mall. The crowd stretched from the Capitol to about 200 hundred yards shy of the hill leading up to the Washington Monument.
How the Park Service estimates crowd size on the mall
Don't ask me how many people I thought was there. I haven't a clue.
Photos comparing the Mall after the Inauguration and after yesterday's rally
nutmeg, sorry we missed you yesterday.