That 2 million figure, reported in an English newspaper, is totally bogus. It stemmed from inflating an already fictive number of 1 million to 1.5 million attributed to ABC News and announced at the rally itself. As I noted earlier today, given that 2 million (or thereabouts) was the number kicked around for Barack Obama's inauguration, there was no way that they crowd on Saturday came close to that magnitude. The Daily Mail, the Brit paper responsible for the 2 million figure, has published a story today claiming "as many as one million people" attended. They'd don't give a source for that estimate.
What about the low estimate, which ABC seems to be sticking by?:
ABCNews.com reported an approximate figure of 60,000 to 70,000 protesters, attributed to the Washington, D.C., fire department. In its reports, ABC News Radio described the crowd as "tens of thousands."
As does stat-geek Nate Silver, who writes:
This was not a small rally. It was also not, in comparison with something like the 2006 pro-immigration protests, a particularly large rally. It was a business-as-usual sort of rally. Mock the protesters at your peril: business as usual suddenly isn't so good for Democrats these days, and the sentiments of the 70,000 people who marched on Washington surely mirror those of millions more sitting at home.
Beyond the bits posted down the blog a bit, here's a schematic from USA Today on how the park police estimates crowds (before they stopped doing that):
When you look at the above, a figure of 250,000, bandied about by some folks who take their crowd math seriously (such as Rand Simberg), starts to seem very plausible.
Schematic courtesy of Moderate in the Middle.
Does it matter if the crowd was 70,000 or 100,000 or 200,000 or more? Probably not so much, but it shouldn't be this difficult to get a basic head count for an extensively photographed and recorded event, should it?
Here's Reason.tv's on-the-scene report of the event. Approximately 6 minutes long.