Mahantango Valley Farm is a late 19th-century painting by an unknown artist, executed in oil on a window shade. The work presents a detailed and orderly view of a rural farmstead, featuring multiple barns, a farmhouse, and various outbuildings set within a fenced landscape. The composition is arranged in a flattened, schematic style typical of American folk art, with clear outlines and a bright, even palette. The scene includes livestock such as horses, cows, and chickens, as well as several figures engaged in daily activities around the farm.

Rows of trees, cultivated fields, and distant hills form the backdrop, while a prominent American flag flies near the house. The artist uses a high viewpoint to display the entire property, emphasizing the neat divisions of land and the abundance of the farm. The red roofs and pale siding of the buildings stand out against the vivid greens and browns of the landscape. This painting belongs to a tradition of American folk art in the late 19th century, when rural life and agricultural prosperity were common subjects.

Works of this type were often created by self-taught artists and sometimes served as records of family farms or local pride. Mahantango Valley Farm is in the collection of the National Gallery of Art in Washington.