Describe the types of subjects preferred by the painters typically associated with the Hudson River School?

The Hudson River School is a term used to describe
American artists who were painting the suibject of
landscapes of the area around the Hudson River Valley in the state of New York in the
mid-1800's, roughly the same time period as the advent of the Impressionists in France. 
These painters depicted romantic landscapes where Americans were exploring, settling,
and living peacefully in harmony with nature.  The Hudson River school artists were the
Ralph Waldo Emerson/Henry Thoreaus of the art world.

Thomas
Cole is generally recognized as the first of the "Hudson River School" painters; Asher
Durand and Albert Bierstadt are other well-known artists affiliated with this group. 
The irony of the Hudson River School painters and their
subject matter is that they were depicting the romance and
beauty of the American wilderness even as Northern states continued to speedily
industrialize its cities and begin to chip away at the agricultural lifestyles of many
Americans.