This report presents State-level corn production cost and return estimates for the 1991 production year, along with coefficients of variation for each cost item. Per-acre costs are highly variable among States due to differences in production practices, inputs, and type and size of machines used in corn production. Total per-acre economic costs varied from $231 in South Dakota to $381 in Colorado. Corn yields varied significantly, from about 82 bushels in Ohio to 147 bushels per planted acre in Colorado. Methods used to develop the State-level production costs and returns for 199'1 are the same as those used to develop regional and U.S. weighted averages published in the Economic Indicators of the Farm Sector: Costs of Production, 1991--Major Field Crops & Livestock and Dairy. State-level estimates should be used for general discussion only, because statistical reliability diminishes for estimates below the regional and U.S. levels due to sample size. Coefficients of variation included in this report are an indicator of the statistical reliability of each estimate.