This paper discusses how marginal cities surrounded by rich hinterlands in geographies of conflict display city-building processes that transform them into emergent geographies of spatial accumulation. Embracing recent debates on geographies of accumulation in the global South, this paper reveals three interrelated strategies that shape capitalist urbanisation in marginal cities of conflict. The empirical findings of a case study in the Colombian Pacific region indicate that: 1) extractive economies supported by national neoliberal policies nurture weak governance, as reflected in city-building processes that increase sociospatial segregation; 2) the circulation of illegal capital within status quo spatial politics seems to result in rapid urban transformations via land use changes; and 3) spatial accumulation in marginal urban settlements conceals processes of systematic social injustice through euphemisms of economic development. This paper contributes to new conceptualisations derived from an analysis of spatial transformations in marginal(ised) cities under geopolitical economies of violence.