Social workers are increasingly working in primary care clinics that provide Integrated Behavioral Healthcare (IBH) in which a patient’s physical, behavioral, and social determinants of health are addressed on a collaborative team. Co-location, where care is housed in the same physical space, is a key element of IBH. Yet, little is known about the rate of social workers co-located with primary care physicians (PCPs). This study serves as a benchmark of the growth of IBH and continued monitoring of co-location is needed to ensure social work workforce planning and training are aligned with changing models of care. Further, identifying mechanisms to support social work education, current providers, and health systems to increase IBH implementation is greatly needed.