Why do some ethnic groups produce local political leaders while others do not? We argue that the spatial distribution of ethnic groups within cities — particularly their concentration into ethnic enclaves — shapes political candidate emergence. Ethnic enclaves facilitate leadership by reducing mobilization costs, enabling targeted public goods provision, and fostering dense social and economic networks. Using a novel approach that combines machine learning classification of candidates’ ethnic ancestries with spatial measures of ethnic clustering, we analyze data from 638 U.S. cities over five decades. We find that greater geographic clustering significantly increases both the emergence and electoral success of co-ethnic candidates, especially in city council elections. This relationship is nonlinear, intensifying beyond a threshold of spatial concentration. Our findings demonstrate that spatial concentration, beyond simple population share, shapes pathways to local political leadership.