One-third of the respondents, 33 percent, said they are undecided, indicating that voter preferences have not jelled.
Seven Democrats are competing for the nomination to challenge Gov. Larry Hogan, who is vying to become the first Republican governor reelected in the state in 60 years. The filing deadline is Feb. 27 and the primary election will be held June 26.
Hogan has high approval ratings and a formidable war chest. Democrats are hoping to ride a wave of opposition to President Trump and the GOP-controlled Congress to oust him in November.
The Gonzales poll found the rest of the Democratic field in the single digits. State Sen. Richard S. Madaleno Jr. (Montgomery) had support from about 5 percent of respondents, followed by 2 percent for Krishanti Vignarajah, who was a policy adviser for first lady Michelle Obama, and 1 percent apiece for technology entrepreneur Alec Ross and lawyer Jim Shea.
Baker's lead is driven largely by the Washington suburbs, where 44 percent of Democrats support him, compared to about 10 percent in other parts of the state. The region includes his home turf in deep-blue Prince George's County, along with Montgomery County, a Democratic stronghold that is the state's most populous jurisdiction, and Charles, Calvert and St. Mary's counties.
Kamenetz led the field in the suburbs around Baltimore City, with support from 29 percent of Democrats in Anne Arundel, Baltimore, Harford and Howard counties.
Patrick Gonzales of Gonzales research said the candidates face a tough challenge in trying to distinguish themselves during the primary contest, in part because their policy differences are negligible. He added that picking up support from advocacy groups and community organizers will be critical.
In primaries, he said, "the grass-roots component plays a much more determinative role than in general elections."
Respondents said their top political priority this year is "removing Donald Trump" from office (41 percent), compared to 25 percent who said they are most concerned about education, 19 percent for the economy and jobs, and 5 percent apiece for climate change and immigration.
Gonzales Research conducted the survey between Dec. 27 and Jan. 5. The poll has a margin of error of 4.5 percentage points.
Scott Clement contributed to this report