This article rethinks how colonial presence and foreign settlements reconfigured urban spaces beyond the treaty-port system by examining Chengdu, an inland, non-treaty-port city. Focusing on the 1930 boundary-wall controversy at West China Union University, a missionary college, it shows that anti-imperialism was refracted through local expectations of access to space and how everyday spatial practices had blurred the line between foreign enclave and local community. In the absence of colonial infrastructures, WCUU pursued indigenizing strategies to embed themselves in urban life; its later move to enclose the campus with walls was criticized as imperialist encroachment. Occurring amid heightened nationalism, the controversy drew force both from nationalist idioms and from ordinary residents’ everyday grievances—economic strain, insecurity, and disruptions to daily routines—in a notably turbulent interwar Chengdu. The conflict brought to the fore two visions of Chengdu’s urban identity: one championed by Western-educated local elites and another articulated by local people defending what they understood as public space. Moreover, I demonstrate how missionary institutions in less overtly colonial settings grappled with the contradictions inherent in their liminal status—simultaneously functioning as colonial enclaves and aspiring to integrate into local society.