On November 15, 2024, the California Department of Public Health (CDPH) confirmed the first reported case of clade I mpox in the United States. This individual had recently traveled to areas experiencing clade I monkeypox virus (MPXV) transmission and sought medical care for mpox symptoms in the United States. Consistent with other recent clade I mpox cases, the patient has relatively mild illness and is recovering. CDC and the local and state health departments are investigating potential contacts; no additional cases in the United States have been detected as of November 18, 2024. The risk of clade I mpox to the public in the United States remains low.