Trump secured 17% support, according to the Suffolk University/USA Today survey
. Former Florida Gov. Jeb Bush garnered 14%, while the rest of the 2016 field remained in single digits: Wisconsin Gov. Scott Walker, the newest entrant to the race, was at 8%; Texas Sen. Ted Cruz at 6%; Florida Sen. Marco Rubio at 5%; Kentucky Sen. Rand Paul, retired neurosurgeon Ben Carson and former Arkansas Gov. Mike Huckabee at 4%; and New Jersey Gov. Chris Christie at 3%.
All other Republican hopefuls received less than 2% of the vote -- and about one-third of GOP voters -- 30% -- remain undecided about who they will back.
The poll's marrgin of error is plus or minus 5.25 percentage points.
Trump's ascendance in the polls follows widespread media coverage of his comments about undocumented Mexican immigrants, whom he has disparaged despite varying levels of condemnation from the rest of the Republican field.
"Trump is making daily headlines in advance of the primary season," said Suffolk University poll director David Paleologos in a statement accompanying the poll results. "This has vaulted him to the top of the pack on the backs of conservative voters."
Gallup issued a separate poll on Tuesday
showing 41% of Republicans said they considered Trump a "serious candidate."
National polls -- even those in the summer of 2015 -- have become more meaningful in 2016, given television networks' decisions to use them to determine which of the 17 Republican presidential hopefuls make the first GOP debates. Many lesser-known candidates have criticized these policies.
If Trump were to earn the nomination, Clinton defeats him soundly by 17 points, according to the Suffolk survey.