Information inequity is a central concern in this information age, and many recognize the public library as a key player in bridging such inequity. Using the Public Libraries Survey and Census data at the census tract level, this study examines more than 9,000 public library systems across the United States. It evaluates disparities existing in public library systems' service levels, and the extent to which these variations are associated with neighborhood socio-economic characteristics, such as income and urbanization levels. Descriptive statistics and Gini coefficients indicate significant variations across library systems. Results of the multiple regression analyses show that library systems in lower-income or rural neighborhoods offer a lower level of service per capita compared to their counterparts in higher income or urban neighborhoods. Systems in lower-income or rural neighborhoods tend to have shorter hours, less staff and programs, and smaller collection size In light of these prevalent disparities in service levels, the study suggests a need to fundamentally evaluate the current library funding mechanisms. It also suggests that public library and information behavior studies should include information environment variables to further investigate how individuals' information decisions might be affected by this structural information inequity.