A. Multiple regression showed that, when adjusting for age, age2, scanner, sex, and genetic ancestry, family income was significantly logarithmically associated with children’s total cortical surface area, such that the steepest gradient was present at the lower end of the income spectrum (β = −0.19; p = 0.004). Income data are presented here on the untransformed scale, fitted with a logarithmic curve, to enable visualization of this asymptotic relationship. This differential rate of change is visualized with the brain maps, where the steepest change in cortical surface area per unit income is visualized with warm colors and the shallowest change in cortical surface area per unit income is visualized with cool colors. B. When adjusting for age, age2, scanner, sex, and genetic ancestry, ln(family income) was significantly associated with surface area in widespread regions of children’s bilateral frontal, temporal and parietal lobes. Relationships were strongest in bilateral inferior temporal, insula and inferior frontal gyrus, and in the right occipital and medial prefrontal cortex. C. When adjusting for age, age2, scanner, sex, genetic ancestry, and parent education, ln(family income) was significantly associated with surface area in a smaller number of regions including bilateral inferior frontal, cingulate, insula, and inferior temporal regions and in the right superior frontal and precuneus cortex. Maps are thresholded at p < .05 (FDR correction). More stringent FDR correction thresholds of .01 and .001 are shown in .