ALBANY — With less than two months before the Democratic primary in New York, Gov. Andrew M. Cuomo has maintained a formidable lead over his opponent, Cynthia Nixon, with large, double-digit margins in all demographic groups, according to a poll released on Wednesday.

The Quinnipiac University poll of 415 registered Democrats found that Mr. Cuomo, who is seeking a third term in November, leads Ms. Nixon, the actress and educational activist making her first run for public office, by 59 percent to 23 percent. That 36-point margin is a marked increase from a 22-point lead he held in a university poll released in May.

Ms. Nixon has been steadily picking up endorsements, many from the same progressive networks that backed Alexandria Ocasio-Cortez in her upset primary victory in June over Representative Joseph Crowley. But that support has not seemed to move the needle among the poll respondents.

Among Democrats, Mr. Cuomo, 60, leads among men, women and white voters, with his strongest support among blacks and Latinos.