This paper analyzes the spatial operations of power in a Himalayan borderland between Nepal and China to argue that border regimes are made, maintained, and performed as territorial processes of control over distinct socio-cultural identities and political economic practices. I make this argument by writing a boundary biography (Megoran, 2006, 2012) about a fence, bringing both history and ethnography to bear on border studies. Specifically, this biography analyzes the Nepal-China border at Mustang-Tibet in two distinct dimensions: 1) the physical (or external) location of the border as a marker of state territory between Nepal and China; and 2) the social and cultural (or internal) location of the border for borderland populations of Tibetan ethnicity. In correspondence to Salter’s (2011) formal, practical, and popular registers of bordering, I use ethnography, readings of diplomatic history, and policy analysis to examine social-political transformations at the Nepal-China border through three specific changes over time. These key moments reflect important state interventions which together shape how the Mustang-Tibet border is experienced in Himalayan borderland lives today. In so doing, this biography shows how borders materialize, dematerialize, and rematerialize and how local populations' identities and geographic imaginaries are influenced and oriented by the border (Sahlins, 1989). By demonstrating how border lives are often shaped and maintained with and across the border rather than against the border itself, this study presents emerging research on Asian borderlands to rethink classic concepts on bordering developed in European and wider global contexts.