Madeline Jones, 19, faces multiple charges after she went missing with her 1-year-old son, William, according to the Mesa Police Department.
The pair had been missing since June after her parents allegedly helped Madeline deny custody of her son to the boy's father, Jacob Gouchenour.
Madeline's parents, Roland and Cassandra, were arrested after Mesa police submitted charges against them. The two were detained at Phoenix Sky Harbor International Airport on September 27.
Police say Madeline was located Monday afternoon northeast of San Diego in Ramona, California, after detectives developed information on her location.
With the assistance of the U.S. Marshals, Madeline and William were detained without incident.
Madeline is being held at a detention facility in Santee, California awaiting extradition back to Arizona.
Police say Madeline is facing charges for custodial interference for keeping William from his father.
William is in custody of Health and Human Services, according to police.
Gouchenour was granted sole custody during the incident and will be reunited with William, police said.