The GIS methods used to identify optimum locations for mobile pyrolysis units in the North Central (NC) region of the U.S. are presented in this paper. Optimum locations were based on feedstock availability. The feedstocks used in the study were corn stover and bioenergy sorghum. For corn stover, 10 year (1999-2008) average corn grain production values were determined for each county in the NC region. Feedstock harvest rates were limited to 25% of the available corn stover leaving 75% for erosion control and soil improvement. LaSalle County, Illinois, was used as a pilot study for the corn stover analysis. For bioenergy sorghum, it was assumed that the production rate was 15 Mg/ha and that bioenergy sorghum would be planted in place of grain sorghum. It was assumed that 100% of the bioenergy sorghum would be harvested for pyrolysis feedstock. ArcGIS and ModelBuilder were used for this feedstock assessment study. A square grid was placed over a map of fields planted with com and sorghum in 2008. The size of the harvest grid was 6,200 x 6,200 m for the corn stover and 20,000 x 20,000 m for the bioenergy sorghum. The sizes of the harvest grids were based on, 1) the mobile pyrolysis unit requires feedstock at a rate of 80,000 lbs/day, and 2) the mobile pyrolysis unit would remain in place for 6 months. It was also assumed that the mobile pyrolysis unit would be located in the center of the grid and that the average feedstock hauling distance from the field to the mobile unit would be one half the grid size. Therefore hauling distances were 3,100 m for corn stover and 10,000 m for bioenergy sorghum. These short feedstock hauling distances demonstrate a primary advantage of mobile pyrolysis units over a central bioenergy plant. The top 100 locations for corn stover feedstock availability were determined with 57 sites in Illinois, 29 in Nebraska, and 14 in Iowa. The top 50 locations for bioenergy sorghum feedstock availability were also determined with 35 sites in Nebraska and 15 in South Dakota.