You might have better luck asking this question on /r/college (check out the sidebar, which has resources for scholarships and financial aid) and /r/ApplyingToCollege. In addition, individual schools will often have smaller scholarship programs for students who meet various criteria, including national origin, local origin (ie, individual towns and cities), ethnic or religious identity, and occasionally chosen major. In general, however, the majority of money is probably going to come from individual schools, often through things such as the National Merit Scholarship. Most national organizations, such as the American Historical Association, are more focused on supporting advanced PhD students and PhD holders, rather than undergrads.