It is well established that political parties play a key role as gatekeepers to elected office. This article explores the local determinants of a diverse candidate pool. In particular, we seek to uncover the district- or riding-specific party factors that are related to women's participation in the parties’ candidate nomination stages. That is, why do some nomination races in a party have no women contestants, while others have many? Using data from an original survey of party constituency association presidents, as well as extensive nomination data from Elections Canada, we demonstrate that a number of local factors are related to the presence of women contesting a party's nomination. Local party associations with a woman serving as president, as well as associations that hold earlier and longer nominations, are significantly more likely to see a woman enter the contest. The results are important since they call attention to what parties do at the grassroots level, as well as highlight practical solutions for parties seeking to have more diversity in their candidate pool.