The Los Angeles County Sheriff's Department said the standoff ended peacefully around 3:30 a.m.
The woman spent approximately 22 hours holed up in the patio area of a home in the Woodland Park Mobile Estates.
Police said she called rescuers for a medical emergency Thursday morning, but when they responded, she pulled out a gun and barricaded herself.
The woman has been taken to a local hospital to be checked out.
No injuries were reported.