Poor children begin school with fewer academic skills than their nonpoor peers, and these disparities translate into lower achievement, educational attainment, and economic stability in adulthood. Child poverty research traditionally focuses on urban or rural poor, but a shifting spatial orientation of poverty necessitates a richer examination of how urbanicity intersects with economic disadvantage. Combining geospatial administrative data with longitudinal survey data on poor children from kindergarten through second grade (N ≈ 2,950), this project explored how differences in community-level resources and stressors across urbanicity explain variation in achievement. Resources and stressors increased in more urbanized communities and were associated with academic achievement. Both mediated differences in poor children’s achievement. Mediation was both direct and indirect, operating through cognitive stimulation and parental warmth.