The purpose of this chapter is to explain the evolution and current institutional and normative design of the local government structure and intergovernmental relations of Mexico City and of the Valley of Mexico. Accordingly, I will examine the origins and the rationales of Mexico City’s urban subdivisions, as well as their legal status, institutions, structures, and competences. Moreover, in this chapter I discuss the rules concerning the subdivision and amalgamation of local government units in Mexico City and the institutions and forums that guarantee coordination across the subdivisions. Furthermore, I analyze the relationship between civil society and institutional reform of Mexico City’s governmental structures. Finally, a reflection is developed on the legitimacy and efficiency of Mexico City’s urban subdivisions and on possible future developments.