Measurements of ant colony sizes and neighboring colony spatial structure figure importantly in a variety of socio-biological considerations. In this study, we used mass-marking and recapture techniques to quantify the foraging distribution and abundance of red imported fire ants, Solenopsis invicta Buren, on individual bait cards from neighboring polygyne (multiple queens) colonies. Ants in six to eight adjacent colonies, at each of 10 sites, were mass-marked a unique color. Ants were collected at olive-oil baits in a 10 by 10-m area consisting of 61 baits at each site. Stepwise nonlinear regression showed that the distance to baits, colony size, and average internidal (between nests) spacing were significant predictors of the foraging distribution of ants from colonies. Most marked ants were collected within ≈4 m of their colony. Foraging was more constrained at closer internidal distances. As internidal distances increased, colony foraging distances increased. There was a significant difference in the number of observed ants from colonies on individual baits compared with the expected number from the regression model. A χ² analysis showed that high numbers of ants on individual baits from a colony had a significant negative effect on the number of foragers from adjacent colonies. Results show ≈66% of the variation in foraging can be explained through colony size, location, and recruiting ability; however, foraging interference among ants from adjacent colonies occurs and may result in unequal sharing of resources (i.e., resource partitioning) among colonies.