Access to housing is an important manifestation of structural racism and discrimination, and birth outcomes show wide health disparities, but few studies have examined eviction and birth outcomes. This multilevel study merged data from the Eviction Lab on 2015 eviction judgements and records with the National Center for Health Statistics natality dataset. The analytic sample included 2,950,965 births across 5924 counties in 45 states. Outcomes of interest were low birthweight (<2500 g; LBW) and preterm birth (<37 weeks gestation; PTB). We fit generalised estimating equations to account for clustering within county and a logistic distribution to estimate the odds ratio of LBW or PTB associated with the county‐level eviction rate, with control for individual‐ and county‐level characteristics. Results were calculated separately for non‐Hispanic white, non‐Hispanic black and Hispanic mothers. After adjustment for covariates, living in the counties in the highest quartile of eviction was associated with a 12–13% increased odds of LBW. The magnitude of association with PTB was not as large. Non‐Hispanic black women were more likely to live in counties in the highest quartile of eviction rate (43%, vs. 23% for white women and 23% for Hispanic women) or filing rate (44%, vs. 23% for white and 18% for Hispanic). The association between eviction rate and LBW/PTB was strongest for black women, while there was essentially no association among Hispanic women. Housing instability may be a key social determinant of poor birth outcomes and should be considered in state and local maternal and child health policy and programming.