While modeled estimates and studies in contaminated areas indicate high lead exposure among children in Bihar, India, local data on lead exposure in the child population is limited. To characterize lead exposure, and assess potential sources of lead exposure among a state-representative sample of children and their pregnant mothers residing in Bihar. Blood samples were collected from 697 children under five and 55 pregnant women from eight districts in Bihar. Blood lead levels were determined using capillary blood and a portable lead analyzer. Household demographics, home environment, behavior, and nutrition information were collected through computer-assisted personal interviews with primary caregivers. Logistic regression was used to assess associations between potential risk factors and elevated blood lead levels. More than 90% of children and 80% of pregnant women reported blood lead levels ≥5 μg/dL. Living near a lead-related industry and pica behavior of eating soil were significantly associated with increased odds of having elevated blood lead levels. Additional risk factors for having a blood level ≥5 μg/dL included the use of skin lightning cream (aOR = 5.11, 95%CI: 1.62, 16.16) and the use of eyeliners (aOR = 2.81, 95%CI: 1.14, 6.93). Having blood lead levels ≥10 μg/dL was also significantly associated with the household member who had an occupation or hobby involving the use of lead (aOR = 1.75, 95%CI: 1.13, 2.72). Elevated blood lead levels were prevalent among children and pregnant women in Bihar, indicating the urgent need for a comprehensive lead poisoning prevention strategy.