Contemporary discussions of immigrant assimilation in the United States often take the experience of the late nineteenth and early twentieth centuries as a benchmark, yet significant gaps remain in our understanding of the generality and rate of immigrant progress during that era. Using four decades of Integrated Public Use Microdata Samples census microdata, we utilize both ordinary least squares microdata regression and double cohort methodology to examine socioeconomic assimilation across arrival cohort and country of origin during the Ellis Island era. Our results show, contrary to some writing, that while the first generation (the foreign born) exhibit decidedly inferior labor market outcomes, socioeconomic attainment (measured by Socio-Economic Index points) increased quickly with duration in the United States. Persons of the second generation and those of mixed parentage show much less penalty than immigrants. At the same time, we uncover differences in outcome by European region that do not disappear over the decades we examine.