The fire was reported at about 8:45 a.m. at 371 Jimno Ave.
People at the house knew the child was inside and a Pittsburg police officer was able find her and pull her out before flames got to her, Hopkins said.
She appeared to be uninjured but was taken to a hospital along with two other residents.
Firefighters had the one-alarm blaze under control by about 9 a.m., Hopkins said.
Nearby Power Avenue was closed to traffic during the incident.
The house is so badly damaged, it's uninhabitable and the American Red Cross has been called to help two adults and three children, Hopkins said.