Libertarian presidential nominee Gary Johnson ranks third with 16 percent.
Republican nominee addresses supporters at large rally
The 2016 race has created an unprecedented gap in campaign fundraising.
Early voting begins in late September.
The town hall was interrupted several times by protesters.
"I fundamentally believe that the first and foremost priority is to fix the unlawful immigration."
Trump is debating softening his immigration proposals.
The public, unsecured network mocks Clinton's email controversy.