Theoretical models have posited that social contexts influence parental attitudes, which in turn modulate parental behaviors. The current study asks whether parental attitudes on bilingualism differ by local language context and whether parents who perceive bilingualism as more valuable are more likely to engage in activities with their child in their home language. We synthesize theoretical models with insights from family language policy in an ecological framework of bilingual development and test these relations in a U.S. sample of parents in 42 states. By capturing parents' perceived value of bilingualism with an online survey (n = 319) and linking responses to U.S. census data, we explored relations among local multilingualism, perceptions of the value of bilingualism, and parents' language practices. We found that parents who lived in more multilingual areas held more positive attitudes toward bilingualism, but the contribution of local multilingualism varied by language background. Local multilingualism mattered most for English-speaking parents who had never tried to learn another language, with those who lived in more multilingual areas reporting more positive perceptions of bilingualism. We also found that for parents of young children exposed to a non-English language (n = 136), those who valued bilingualism for their child were also more likely to participate in activities using their home language. These findings show how distal societal factors, such as local multilingualism, can have a cascading association with parents' perceived value of bilingualism and parents' language practices with their young children in the United States.