This report provides an overview of the system that provides services and supports to individuals with intellectual and developmental disabilities (I/DD) in California. With a mixture of state and Medicaid funding, a network of twenty-one private nonprofit corporations called “regional centers” allocate benefits to eligible consumers throughout the state. This report describes the laws, institutions, and demographic trends that are shaping the regional center system. It begins with a summary of its structure and historical development, provides an overview of the state and federal funding sources upon which it relies, and closes with a discussion of the challenges that are taxing its capacity to carry out its intended goals.