In October 2025, three clade I mpox cases were identified in Southern California who did not report travel history, or contact with one another. This is indicative of community spread of clade I monkeypox virus (MPXV) in California. All prior cases of clade I mpox in California and in the United States have been associated with international travel to areas in which spread of clade I MPXV is ongoing. The California Department of Public Health (CDPH) continues to work closely with local public health departments to conduct enhanced surveillance to detect additional clade I cases. There have also been recent increases in clade II mpox cases reported in California.