Sen. Bernie Sanders (I-Vt.) pauses during a political rally in Madison, Wis., on Wednesday. (Michael P. King/Wisconsin State Journal/AP)

COUNCIL BLUFFS, Iowa — Another day on the presidential campaign trail, another crowd of eye-popping size for Bernie Sanders.

The independent senator from Vermont attracted more than 2,500 people to a convention center here on Friday night as part of his continued quest to lead a "political revolution" and win the Democratic nomination in a field that also includes Hillary Rodham Clinton.

It was by far the largest draw in Iowa, the nation’s first caucus state, by any White House hopeful this cycle — though there were plenty of Sanders fans in the crowd who came across the river from Nebraska.

[In Bernie Sanders, an unlikely — but real — threat to Hillary Clinton]

Still, by any measure, it was impressive gathering and the latest to underscore the strength of the Sanders phenomenon. Earlier this week, 10,000 people showed up in Madison, Wis., to hear Sanders, a self-described democratic socialist, decry the "grotesque level" of income inequality in the country and the influence of the "billionaire class" on its politics.

His message was much the same Friday, as Sanders laid out priorities that include guaranteeing family leave and sick time for workers and making health care a national right, as well as fighting climate change and providing public financing for elections.

Among the enthusiastic supporters who turned out was William Pugh, a retired journalist and teacher who lives across the river in Omaha.

"He's the only truth-speaker out there," Pugh, 62, said of Sanders. "He calls the system for what it is. It's broken, it's corrupt, and it's an oligarchy. ... If he's not electable, there's no hope for this country."

Sanders, who's in the middle of a three-day swing through Iowa, drew a crowd of close to 800 to Des Moines, the state's largest city, last month. Clinton attracted a crowd nearly that size last month in Des Moines as well.

Appearing Friday at Dartmouth College in New Hampshire, the country's first primary state, Clinton attracted about 850 people.

[Bernie Sanders packs thousands into a Denver gymnasium]

Candidates appear so often in Iowa and New Hampshire that their audiences can be smaller there than in states they visit less frequently. Sanders's larger crowds in recent weeks include about 3,000 in Minneapolis and more than 5,000 in Denver.