Donald Daniels, 26, faces a long prison term when Judge Frank M. D’Addabbo Jr. sentences him on Dec. 7.
Daniels and the victim, a woman in her 20s, knew each other, police said.
They were riding in a car and Daniels told the woman he had something to show her, East Hartford police Lt. Josh Litwin said. Daniels led the woman into woods off Burnside Avenue, where he sexually assaulted her at gunpoint, Litwin said.
The woman was able to run away and eventually made her way to a hospital. Police were notified the day of the assault.
Daniels was taken into custody in July after Manchester police, who knew he was wanted for the sexual assault, spotted him at a store parking lot on West Middle Turnpike.
Daniels has been jailed in lieu of $350,000 bail since his July 28, 2017, arrest.