The work of a school principal is complex and multi-faceted. Expectations for the role are steadily rising, and questions have surfaced regarding the capacity of principals to meet all of these expectations. In recent years, Washington state has engaged in numerous instructional improvement and accountability initiatives, including revisions to the way in which educators are evaluated. A sizable portion of the workload associated with these initiatives rest on the shoulders of school principals and assistant principals. A recent study noted that principals work an average of 59 hours per week (Lavigne, Shakman, Zweig, & Zeller, 2016). Little systematic and statewide knowledge exists about the nature of the school administrator workforce and the career patterns of principals in Washington state. This study aims to provide insight into the demographics of principals and assistant principals, their retention, mobility, and career patterns, and the equity issues associated with differences across schools in Washington state.