This report describes the demographic and educational characteristics of the U.S. immigrant population and discusses barriers faced by legal immigrants seeking to enroll in postsecondary education. The report focuses on older immigrants, who confront significant challenges in understanding and gaining access to the U.S. system of higher education because they did not attend American primary and secondary schools. It also examines the characteristics of and the barriers to persistence and completion faced by immigrant students who do enroll in college--a group that makes up 12 percent of the U.S. undergraduate population but has received relatively little attention in the public policy arena. Findings center around the following themes: (1) Immigrant groups vary considerably in their access to and success in higher education; (2) Although immigrants face challenges in gaining access to higher education, they make up a significant portion of American undergraduates; (3) Immigrant undergraduates differ from their native-born counterparts in a number of important ways; (4) Immigrant college students vary considerably by race and ethnicity; and (5) Immigrants face multiple barriers in gaining access to higher education and completing a college degree. Policy and program ideas are suggested. Includes appendix: Data Sources and Limitations. (Contains 9 notes, 16 figures, and 2 tables.)