Over the last twenty years, both crop production and agricultural payments have shifted toward larger operations. This study examines whether payments from federal farm programs contributed to increased concentration of cropland and farmland. Using zip code—level data constructed from the microfiles of the 1987–2002 agriculture censuses we examine the association between government payments per acre and subsequent growth in land concentration. A semiparametric generalized additive model (GAM) controls for location and historical concentration, sales per acre, and ratio of cropland area to zip code area. Findings indicate, both with and without nonparametric controls, government payments are strongly associated with subsequent concentration growth. Copyright 2008, Oxford University Press.