There is no absolute prototype for a farmhouse, but most of us can recognize one when we see it. By definition the originals were located on farms and were integral to the life and work of those farm families who lived there.
Depending on when and where those homes were built, they could be made of stone, brick, shingles or clapboard. Most farmhouses had porches since there was no air conditioning and many farm and family chores were undertaken there. The porch roof provided shelter from the sun and rain yet allowed the cool breezes to flow through and help make those steamy summers tolerable.
The center of family life in the farmhouse was the kitchen. Meals were prepared and often eaten there as well as home pickling and canning for the long winters (in the North). In the older farmhouses, a cooking fireplace was essential. Additional fireplaces were used to heat as many rooms as possible.
I live in an old farmhouse originally built around 1790 and then added onto in the 1800s and more recently added onto by my family. I have come to appreciate the simple detailing the wide board floors and beautiful fireplaces.