No one knows how many Americans can trace their ancestry to the Czech Lands. According to a recent study, about 2 million people in the United States claim to have at least one parent or grandparent who was a native Czech speaker, but this is hardly indicative of the true number. We do know that some 400,000 Czechs immigrated to the United States, the vast majority of them between the liberal revolutions of 1848 and the onset of World War I.