OBJECTIVES: The first known COVID-19 outbreak in a long-term care facility in the United States was identified on February 28, 2020, in King County, Washington. That facility became the initial U.S. epicenter of the COVID-19 pandemic when they discovered 129 cases associated with the outbreak (81 residents, 34 staff members, and 14 visitors) and 23 persons died. The vulnerability of the elderly population, shared living and social spaces, suboptimal infection control practices, and prolonged contact between residents were identified as contributing factors to the rapid spread of the disease. The first known case of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak in a U.S. inpatient geriatric psychiatry unit was also in King County, Washington, and occurred soon afterward on March 11th, 2020. Between March 11 and March 18, nine inpatients and seven staff members were confirmed to have SARS-CoV-2 infection. This article examines how the swift identification and isolation of confirmed patients, an enhanced infection prevention protocol, and engagement of frontline psychiatric care staff prevented a catastrophic outcome in a vulnerable population. METHODS: Here we describe infection control and nursing-led interventions that were quickly enacted in response to this SARS-CoV-2 outbreak in an inpatient geriatric psychiatry unit. RESULTS: The interventions effectively contained the outbreak, with no further patients and only one staff member testing positive for SARS-CoV-2 over the subsequent 2-month time period. CONCLUSIONS: We share our learnings and preventative infection control measures that can be adapted to a variety of settings to prevent or contain future outbreaks of COVID-19.