It can be difficult to define Catholic university identity in universal terms--or to compare one Catholic institution to another--because Catholic colleges and universities in the United States are diverse in terms of size, location, and mission. This article proposes a rough classification system for Catholic universities that takes into account the various ways they interpret and express their Catholic missions. Each institution has struck its own balance between its role as a Catholic institution in service to the Church and as an American institution in service to an ever-evolving, religiously diverse country. This loose taxonomy can help each Catholic university identify meaningful peers and understand its place in the American Church.