Early in the 19th Century two families, the Allens and Kathans, settled in the Southern Adirondack Mountains of New York State. By 1960's their descendants had isolated themselves in a remote hollow high in the mountains. Below lay the great Sacandaga Valley. Its rich lands rapidly filled with farms, factories and mills.

By the end of the century, the Allens and the Kathans had intermarried: all the residents in the Hollow were related. Because of their isolation, misunderstandings developed between them and the outside world.

The economic disasters of the 1930s shut down the factories and mills. In 1932 the Sacandaga River was dammed, flooding the fertile valley below the Hollow. Forced from their homes, the valley residents sought employment elsewhere, but the Allens and Kathans chose to remain up in the mountains.

More information on the Hollow.

Also, see this New York Times article about the Hollow from 1993:

On a small mountain ridge known as the Hollow, in the foothills of the Adirondacks, indoor plumbing was first installed six years ago and many people still do not have telephones.

There may be a few signs of modernization in the area, which social workers call the Appalachia of the North: Subsistence farmers no longer keep animals inside their homes. Sales people sometimes venture in now. And more parents are sending their children to school, although they say heavy snow on the mountain roads often keeps them from reaching classes during the long winters.

Still, most people in the Hollow, home to several hundred descendants of two farming families that settled here in the early 19th century, continue to make their living as the woodsmen and trappers they have been for nearly 200 years, selling firewood or serving as guides. Few apply for social services, and the authorities rarely intervene in their lives. There are no officials, no leaders, elected or otherwise, in the Hollow, which is 35 miles north of Saratoga Springs and is in the town of Day in the northwestern corner of Saratoga County, bordering Warren County.

The location of Allentown can be found on Google Maps.