The poll conducted by Quinnipiac University in Connecticut indicates Clinton leading several possible Republican candidates by at least 10 percentage points. New Jersey Gov. Chris Christie, who led Clinton by 5 points in a mid-December poll, now trails her 48 percent to 35 percent.
Sen. Rand Paul, R-Ky., fares the best, getting 39 percent in a matchup to Clinton's 49 percent. Sen. Ted Cruz, R-Texas, trails Clinton by 16 points and former Florida Gov. Jeb Bush trails by 14 points.
Clinton leads all comers among independent voters.
The poll found 39 percent of Iowans approve of Obama's job performance while 57 percent disapprove, little changed since mid-December.
Democrats continue to back the president with 77 percent approving and 17 percent disapproving. Among Republicans, a whopping 93 percent disapprove and only 5 percent approve while 59 percent of independents disapprove to 37 percent in his corner.
"Politics is a team sport and the head of the blue team, President Barack Obama, isn't doing well in the eyes of Iowans. But that doesn't seem to be hurting teammate Hillary Clinton who swamps potential 2016 Republican competitors among the same electorate," said Peter Brown, the poll's assistant director. "So much, at least for now, for conventional wisdom that as the president's popularity goes, so goes Democratic hopes for 2016."
Brown said Obama's unpopularity also appears to be doing little damage to Rep. Bruce Braley, D-Iowa, the likely Democratic candidate for the Senate seat now held by Tom Harkin, D-Iowa. The poll gave Braley double-digit leads over possible Republican nominees.
Quinnipiac surveyed 1,411 registered voters March 5-10. The margin of error is 2.6 points.