The siblings were found Wednesday morning.
Adriana Castillo, 9, was considered critical missing and her sister, 11-year-old Ali Abrego, was considered a runaway.
At about 8 p.m. Thursday, the girls' mother returned home from work and discovered they were gone. Police said the two girls were last seen around 4 p.m. near a wooded area behind the Mariposa Villas Apartment Homes on Duncanville Road.
Officers searched the brush near the wooded area, but the brush was too dense and they were unable to pick up any heat signals. Police believe the girls brought snacks and a cellphone with them when they disappeared. However, they were not dressed to spend the night in the elements.
Details about where they were found were not immediately released.