IMPORTANCE: Rates of suicide ideation, severe depression, and acute psychosis have surged, paralleling an increase in emergency department visits for psychiatric emergencies. Mobile crisis services can play an important role in delivering timely, community-based interventions. OBJECTIVE: To assess the national availability of mobile crisis services in mental health treatment facilities and to identify key facility, geographic, and state-level factors associated with the availability of these services. DESIGN, SETTING, AND PARTICIPANTS: This cross-sectional study analyzed data from the 2022 National Substance Use and Mental Health Services Survey, which included 9036 mental health treatment facilities in the US. Facility zip codes were linked to the Agency for Healthcare Research and Quality's Social Determinants of Health database to assess area-level factors. The study population included facilities that reported whether they offered mobile crisis services. Data were analyzed from August to September 2024. MAIN OUTCOMES AND MEASURES: The primary outcome was the availability of mobile crisis services at mental health treatment facilities, as reported by facility directors. Key independent variables included facility characteristics, local area factors, and state Medicaid policies. Logistic regression models were used to examine the associations between these factors and the availability of mobile crisis services. RESULTS: Of 9036 facilities, 1882 (20.8%) reported offering mobile crisis services. Facilities providing integrated dual diagnosis services (marginal effect, 3.44 [95% CI, 1.41-5.53] percentage points), suicide prevention services (marginal effect, 6.74 [95% CI, 4.29-9.20] percentage points), and assertive community treatment (marginal effect, 11.26 [95% CI, 9.02-13.51] percentage points) were significantly more likely to offer mobile health crisis services. Facilities in areas with lower percentages of residents with only a high school education were also more likely to offer mobile crisis services (marginal effect, 1.33 [95% CI, 0.15-2.51] percentage points). CONCLUSIONS AND RELEVANCE: In this cross-sectional study of US mental health facilities, facilities with integrated services and located in areas with certain geographic characteristics were more likely to offer mobile crisis services. Addressing gaps in service availability is essential to improving access to crisis care.