Accessible and affordable early childhood care and education (ECE) is crucial to child, family, and community well-being. High quality ECE programs set the stage for lifelong learning, health, and overall well-being and yield a high rate of return on public investment. Equitable access to ECE remains an intractable challenge in the U.S. and elsewhere. We used spatial analysis to create a single micro-level indicator of ECE affordability for an urban county. This indicator combined information on supply (number of nearby sets), demand (number of children competing for these seats), and cost burden (cost as a percentage of median family income). We measured and mapped the affordability of programs within a 3-mile driving distance of a prototypical family home using a two-step floating catchment area method. Overall, affordability was low, with only 14% of young children having access to ECE that met the federal affordability threshold. Although affordability was inversely related to neighborhood income, not all low-income areas were under-resourced. The ECE affordability indicator can arm community advocates and help policymakers identify inequities and direct resources to the highest-need communities. The computational procedures and mapping techniques applied are flexible and can be scaled up to visualize inequities across large areas (e.g., a province or state), or used at a micro level to identify where in a community a new childcare center would have the most impact.