William Langson Lathrop was an American Impressionist landscape painter and founder of the art colony in New Hope, Pennsylvania, where he was an influential founder of Pennsylvania Impressionism.

American Impressionism was a style of painting related to European Impressionism and practiced by American artists in the United States from the mid-nineteenth century through the beginning of the twentieth. The style is characterized by loose brushwork and vivid colors with a wide array of subject matters but focusing on landscapes and upper-class domestic life.