Authorities said the body was found wrapped in a blanket Thursday morning at the plant in Victorville, about 85 miles north of Los Angeles.
Homicide detectives from the San Bernardino County Sheriff's Department were investigating. The infant's age was not immediately known, but authorities said she appeared to be a newborn.
"Anyone who is aware of a female who has recently given birth and doesn't have that child in her possession is urged to contact" authorities, San Bernardino County Sherriff's Department spokeswoman Jodi Miller told the Victorville Valley Press.
The recycling center serves residents and businesses in the high desert region northeast of Los Angeles and the San Gabriel Mountains.