Based on my experience attending anti-abortion marches (which are always populated by “invisible” people, btw, since apparently about 75% are not seen by the press), I’d say it was around 1 million. There were 450 buses and innumerable people who had come on their own (my plane from Florida was about half full of tea party travelers, some of whom had decided the very day before to buy a ticket and come).
Also, people kept arriving all day and the highways had to be shut down. A guard in one of the nearby buildings (where people had gone to use the bathrooms) said that they had been told to expect only 6-7,000 people, btw! They were completely unprepared for this. Actually, I think the underestimate was intended to make things more difficult for the crowd by letting a gridlock happen and not permitting access to more spacious areas.
However, the crowd was very orderly, and the DC and park police did their best and were very helpful. I did hear someone ask a cop about the numbers shortly before 1:00 pm, and he said about 1.2 million (a number he had gotten from headquarters on his radio).
In any case, they always make aerial shots of events like this (there were helicopters passing overhead filming it), and they can give a fairly accurate count that way. Maybe it would be good to request those photographs, if possible. A count based on Parks Dept. photos was how the press was finally forced to admit that an anti-abortion march they (a) ignored and then (b) claimed to be attended by about 30,000 people was actually attended by at least 500,000 people, back in the 90s. The controversy over that was, in fact, the thing that led the Parks Dept. to stop providing counts.
That seems to be the consensus of many attendees with your experience.
This argument over the actual attendance stat is going to go on for some time, but everyone who followed the event, and everyone who was there, understand that the real story is that this movement is building. The more the left attempts to ignore and minimize it, the bigger it will get.
Poll after poll after poll shows that a clear majority of American citizens do not like the way that congress and the "President" are handling the country, and that they want them to slow down and exercise some fiscal restraint.
The fact that Congress and Obama have shown no indication of backing off their radical leftist agenda is frightening, and even infuriating millions of people. This is only making matters worse for the government, and for us.
The Democrats in power are not only guaranteeing themselves a resounding defeat in the upcoming mid-term elections with this behavior, but are openly risking, and even instigating something much worse.