This chapter explores the geography of China’s social interaction footprint patterns based on a unique location-based social media database. At its heart, a geo-tagged computational framework is designed to extract and aggregate millions of social media users’ space-time footprints for network analysis about human mobility flows at different spatiotemporal scales. Our visual exploration results present evidence in support of the existence of heterogeneous social interaction patterns between peripheral and metropolitan regions. Additional results suggest that footprints are not distributed evenly over time, with substantial travel flows out of and into metropolitan regions during traditional Chinese holiday months. Finally, we quantify new evidence about important roles of tangible market potentials and intangible cultural ties to play in influencing human mobility flows at a detailed spatial degree.