The recent publication of an expansive national dataset, the Integrated Public Use Microdata Sample, allows for new analyses of the historical geography and settlement of various immigrant and ethnic groups in the United States. The present research explores the growth, development, and geographic dispersion of the ethnic Mexican population, and outlines some of the demographic and social characteristics within significant clusters of this population in the United States across the first half of the twentieth century. The analysis does not attempt to overturn other geographies and ethnographies in Mexican American history, but through its ability to elucidate broad, national patterns it is able to create a more dynamic view of settlement, demonstrating the role of immigrants and of women immigrants in particular. Results indicate that place matters: the geographical context of arrival and settlement were key factors in differentiating communities and the lives of those who lived in them.