School district consolidation is a contentious policy debated and implemented in states across the nation. Though consolidation occurred rapidly throughout the 20th century, with the number of districts falling from over 120,000 to approximately 13,000, and several states and communities continue to mandate or incentivize it, little is known about the effects of the policy on student learning or the efficient use of the public’s resources. The purpose of this dissertation is to describe recent school district consolidation in the United States and estimate the effects of one mandatory consolidation policy on student and financial outcomes. Using national and state administrative records and media reports of mergers, I counted the number of consolidations between 2000 and 2015 and examined the characteristics of affected districts. I found that one of every nine districts was part of a consolidation during this period. Most of the mergers melded a very low-enrollment rural district into a much larger neighbor, but some consolidations paired multiple high-enrollment urban districts. Consolidating districts were above-average spenders but generally carried little debt. To examine the efficiency effects of consolidation, I studied student and spending outcomes of a 2004 Arkansas law that established minimum district enrollments. From a differences-in-differences analysis, I found that graduation rates were negatively affected by consolidation while the effect on spending was negligible. Some administrative expense savings, specifically targeted by the legislation, were realized through a reduction in the number of central office personnel, but increases in transportation spending offset half of the small savings. These findings suggest that efficiency improvements should not be expected to automatically follow from school district consolidation. The results of the descriptive analysis, in conjunction with the many mandatory consolidation proposals under consideration in states across the nation, highlight the need for an acceleration of research into the effects of school district consolidation on community resources and student learning and life outcomes.