The horse became stuck when its owner was riding it on a riverbed about 20 feet from shore Saturday evening, the Los Angeles Times reported.
Firefighters used a two-line rope system and tools including backboards and plywood to carry the horse, which was tranquilized during the rescue effort, to shore, said Los Angeles Fire Department spokesman Erik Scott. It took the team of firefighters about four hours to pull off the rescue.
After getting to shore, the horse was airlifted to another location.
"It's not only to save the life of that animal but also to prevent those who are going after it that are untrained from being injured," Scott said.