This paper employs IPUMS United States Census data to study the occupational distribution of
immigrants between 1850 and 2000. Examining occupational diversity is crucial to understanding
how immigrants adjust to a host economy and affect growth. I use occupations as a way of
measuring assimilation. I analyze whether or not the spread of immigrants across occupations
looks like the spread of natives over time. To do this, I create a unique measure of diversity based
on the fractionalization index. I construct occupational diversity indices for each immigrant group
and decade. Results from a case study examination indicate that relative occupational diversity has
increased over time as immigrants have a greater ability to enter a wide array of occupations. I use
empirical models to show that a positive relationship exists between relative occupational
diversity and the immigrant to native ratio.