Immigrants and their children assimilate into US society and the US economy, both in the past and today.

We contribute to the public debate on immigration policy in the United States by providing a long-term, empirical perspective. We develop a novel method of linking individuals across historical Census waves to trace the lives of millions of immigrants in the past and compare their outcomes with immigrants today. We document that upward mobility is just as possible for immigrants today as it was in the early 20th century, and that children of immigrant parents catch up to and frequently exceed the economic outcomes of the children of US-born parents. By our measures, immigrants as a group are no more likely to be incarcerated than those born in the United States, and they assimilate into American culture today at rates comparable to historical standards. Attitudes toward immigrants today are more positive than a century ago, albeit more polarized by political party.