BACKGROUND: The Maintaining Internal Systems and Strengthening Integrated Outside Networks (MISSION) Act of 2018 authorized a major expansion of purchased care in the community for Veterans experiencing access barriers in the Veterans Affairs (VA) health care system. OBJECTIVE: To estimate changes in primary care, mental health, and emergency/urgent care visits in the VA and community fiscal years (FY) 2018-2021 and differences between rural and urban clinics. DESIGN: A national, longitudinal study of VA clinics and outpatient utilization. Clinic-level analysis was conducted to estimate changes in number and proportion of clinic visits provided in the community associated with the MISSION Act adjusting for clinic characteristics and underlying time trends. PARTICIPANTS: In total, 1050 VA clinics and 6.6 million Veterans assigned to primary care. MAIN MEASURES: Number of primary care, mental health, and emergency/urgent care visits provided in the VA and community and the proportion provided in the community. KEY RESULTS: Nationally, community primary care visits increased by 107% (50,611 to 104,923), community mental health visits increased by 167% (100,701 to 268,976), and community emergency/urgent care visits increased by 129% (142,262 to 325,407) from the first quarter of 2018 to last quarter of 2021. In adjusted analysis, after MISSION Act implementation, there was an increase in community visits as a proportion of total clinic visits for emergency/urgent care and mental health but not primary care. Rural clinics had larger increases in the proportion of community visits for primary care and emergency/urgent care than urban clinics. CONCLUSIONS: After the MISSION Act, more outpatient care shifted to the community for emergency/urgent care and mental health care but not primary care. Community care utilization increased more in rural compared to urban clinics for primary care and emergency/urgent care. These findings highlight the challenges and importance of maintaining provider networks in rural areas to ensure access to care.