The Houston Education Research Consortium (HERC), in collaboration with 10 public school districts in the Greater Houston area, set out to better understand the prevalence, patterns, and consequences of student mobility on Houston area students and schools. This brief explores the informal networks of elementary school student mobility in the Greater Houston area across 27 independent school districts (ISDs), which include HERC's 10 school district partners involved in the Student Mobility and Continuous Enrollment project, their 17 neighboring districts, and non-district charter schools. Six mobility networks were identified in the Greater Houston area. These mobility networks crossed district boundaries, and differed in terms of their size, student demographics, and school characteristics. About 70 percent of student mobility that started from a campus in one of the six networks stayed within that same network.