Xiomara Zelaya, 13, and her 9-year-old sister Heidi Moreno were found around 3:15 p.m., nearly 24 hours since the pair took off from their own home in the 300 block of Maine Avenue, according to Richmond police Sgt. Nicole Abetkov.
Abetkov said the teen decided to leave home after getting into a disagreement with her mother over a boy.
Though Xiomara has run away before, this time she decided to bring her sister along, the sergeant said.
Police searched for the girls in Richmond and in San Francisco, where they attend school and lived until recently, and at relatives' homes in Solano County.
Abetkov said investigators found clues about the girls' whereabouts via social media, which led them to the neighbor's home Wednesday afternoon.
Both girls were in good condition, she said