The term "American School" covers a large range of anonymous artists who worked in America from the 17th through 20th centuries; however, it is especially appropriate in cases of itinerant painters or regional painters. The term includes those unknown artists who may or may not have made a living from painting, those who may have worked unrecognized or in isolated or rural areas; artists whose work was not recorded and/or may not have been exhibited; or some, but by no means all, self-taught artists.

The term is particularly valid in American art history, where so many itinerant artists practiced as craftspeople rather than professional artists, and where professional status in the arts was achieved by comparatively few of the many practicing artists in the country.