Cassidy Bejarano was found in Texas in the company of a 25-year-old man from North Carolina.
Bejarano and the man were located after a Texas Department of Safety Officer pulled over the man's car for speeding.
A check of their names revealed that Bejarano was reported missing and endangered.
It is not clear how the two met, but Chandler police said it may have been over the Internet.
On Friday, Bejarano left her home in the 4500 block of West Boston Street in Chandler around 9:30 a.m.
Bejarano did not appear to have taken anything with her, including any money or important medications.
"It's very important that she has her medications. Without her medications she could have some serious complications," Sergeant Joe Favazzo with Chandler Police Department said.
The only clue to her whereabouts was a note left behind that said she was leaving to go to California, but it is was not clear how she would get there or where she would go.
During the search, police contacted bus companies with lines heading to California to see if Bejarano may have tried to take one.
With the help of Phoenix police, officers stopped one bus to check for Bejarano, but did not locate her.
Texas officers have taken the man Bejarano was with into custody, and will be seeking any applicable charges against him.
Bejarano's mother flew out to Amarillo, Texas, on Saturday to pick up Cassidy after she was interviewed by police.
Chandler police said Bejarano appeared safe and unharmed.