The incident occurred near Beach Boulevard and Utica Avenue at about 8:25 p.m., according to police.
The victim, identified as 34-year-old Genevieve Hall, was transported to UCI Medical Center, where she succumbed to her injuries.
Police say witnesses were interviewed at the scene and reported the vehicle involved in the collision failed to stop after striking the bicyclist.
Family members and friends gathered at the scene of the crash Monday. They say the single mother's smile and positive attitude could change your day.
"She was an awesome person. She was a good mom," said Billy Dwyer, the victim's friend.
Hall's brother, Bubba Hall, says the hardest part was telling his 10-year-old nephew that his mom wasn't coming home. He says he can't understand how the driver could just leave the scene.
"They have to sleep at night knowing what they did, and I have to sleep at night knowing my baby sister is not here anymore and my nephew doesn't have a mom," he said.
The investigation is ongoing. No arrests have been made. Investigators say they are looking for a white 2006 to 2013 Chevy Impala with front-end damage.
Anyone who may have witnessed the incident was urged to contact Huntington Beach police at (714) 536-5670.