Sanders drew criticism from local Republicans.
"Bernie Sanders represents what the national Democrat Party has become, which is radically left of everything we've ever known," said Jeremy Bradford, executive director of the Tarrant County Republican Party. "With the rise of the Democrat Socialist wing of the DNC, what was once the radical fringe has become mainstream of their party.
"Bernie Sanders and his far-left ideas are too liberal for Texas and too liberal for Tarrant County."
The Sanders campaign said 2,755 people crowded into Burnett Park to see the candidate.
Some there said they are staunch Sanders supporters; others said they are looking at all the Democratic candidates and want to learn as much as they can about all of them.
"The field is wide open," said Mike McClure, a 58-year-old Fort Worth man who attended the rally with his daughter, Michelle Bonilla, and her children. "But he's on the top of the list."
"He's my No. 1 pick," Bonilla said.
Juliet Wyrick, a 61-year-old from Johnson County, said she voted for Sanders in 2016 and she will vote for him again next year.
"I think he can win the Democratic nomination," she said. "There's a lot of good people now, but we need someone tough, like Bernie."
No matter what, Wyrick said she doesn't want to see a repeat of 2016, when the Democratic Party became so divided. "It splits the vote and we lose," she said.