Indirect land use changes (iLUC) triggered by the expansion of crop-based biofuels has became a critical issue in the debate over biofuels policy. In their Renewable Fuel Standard Programs both US-EPA and the State of California have required measurement of iLUC. Yet the estimates are highly contentious. One critical point of discussion is where the iLUC will take place and this in turn depends on the assumed relationships between international trade and global output distribution. The geography of iLUC matters due to differences in yields, which determine how much land conversion is necessary, and land cover types, which determine the greenhouse-gas emissions of the converted land. This paper tests which of the two trade assumptions used in the leading economic models employed to study iLUC has better support from the historical data on trade and harvested areas of coarse grains.