In this study the authors use longitudinal data from one large school district--Miami-Dade County Public Schools, to investigate the distribution of principals across schools. The authors find schools serving many low-income, non-white, and low-achieving students have principals with less experience, less education, and who attended less selective colleges. This distribution of principals is partially driven by the initial match of first-time principals to schools at the beginning of their careers and is exacerbated by systematic attrition and transfer away from these schools. Supplementing these data with surveys of principals, the authors find principals' stated preferences for school characteristics mirror observed distribution and transfer patterns. Principals prefer to work in easier to serve schools with favorable working conditions which also tend to be schools with fewer poor, minority and/or low-achieving students. Full Models from Discrete-Time Hazard of Leaving Principal Position is appended. (Contains 10 tables and 12 footnotes.) [This paper was supported by the Stanford University K-12 Initiative.]