The United States has admitted more than 3 million refugees since 1980 through official refugee resettlement programs that provide temporary assistance. Scholars have highlighted the success of refugee groups to show the positive impact of governmental programs on assimilation and integration. In the past, however, refugees arrived without formal selection processes or federal support. We examine the integration of historical refugees using a large archive of recorded oral history interviews to understand linguistic attainment and economic outcomes of migrants who arrived before 1940. Using detailed measures of vocabulary, syntax and accented speech, we find that refugee migrants achieved higher levels of English proficiency than did economic migrants, a finding that holds even when comparing migrants from the same country of origin or religious group. This study improves on previous research of immigrant language acquisition, which typically rely on self-reported measures of fluency, and on studies of refugees, which typically assign refugee status based on country-of-birth alone. Our findings are consistent with the hypothesis that refugees, being unable to immediately return to their origin country, may have had greater incentive to learn or be exposed to English, which increased their linguistic attainment. Our results provide an optimistic historical precedent for the incorporation of refugees into American society.