The principal purpose of de Crèvecœur's essay "What is an American" is to describe how European immigrants become Americans and emphasize the advantages of doing so. This is a process de Crèvecœur knew at firsthand, having moved from France to North America in 1755 at the age of nineteen. Having presented an idealized picture of the peace and prosperity of American life, the author makes the point that those immigrants who escaped from poverty in Europe have no reason to love or even acknowledge their countries of birth:
Alas, two thirds of them had no country. Can a wretch who wanders about, who works and starves, whose life is a continual scene of sore affliction or pinching penury; can that man call England or any other kingdom his country?
These immigrants are truly American, since America has provided them with everything they need, everything which their countries of birth withheld from them. The motto of the immigrant, de Crèvecœur says, is "Ubi panis, ibi patria" (where there is bread, there is my homeland). The new world is a place where one can become "a new man, who acts upon new principles; he must therefore entertain new ideas, and form new opinions."
Much of the essay is taken up with specific descriptions of the different parts of America and the way life is lived in these places, but de Crèvecœur always returns to the unity of America and the way in which it offers immigrants opportunities they could never have enjoyed in Europe. He concludes by imagining America herself addressing the new arrivals and promising them prosperity if they will only be "just, grateful and industrious."