Objective Investigate the contributions of Area Deprivation Index (ADI) and geographic location on age-matched birth weight z-scores. Methods A retrospective cohort study of all singleton births >22 weeks’ gestation in Dane County, WI from 1/2016-6/2018. Generalized additive models were adjusted for race/ethnicity, cigarette use, delivery route, pregnancy-related or chronic hypertension, pregestational and gestational diabetes, number of prenatal visits, maternal age, total weight gain, and pre-pregnancy BMI. Results We find evidence of an association between birth weight z-score and spatial location (median p-value: 0.006). With area deprivation, we find no evidence of an association with birth weight z-score (-0.01, 95% CI: -0.03-0.01, p= 0.109). Mean birth weight z-scores were lowest (-0.72) in the urban center of Madison, while mean birth weight z-score was highest (0.18) in rural areas near the northeast, southeast, and southwest county borders. We find an effect of race/ethnicity on birth weight. Conclusion We identified geographic variations in birth weight at a granular level using census block groups and a holistic measure of deprivation, which can inform targeted public health interventions. The lack of evidence of area deprivation on birth outcomes but significant spatial trends demonstrated continued geographic disparities in our healthcare systems.