Understand
The Amish are a community of Christian Anabaptists, related to the Mennonites and Church of the Brethern. The name "Pennsylvania Dutch" is actually a mispronunciation of "Deutsch" or German. The Anabaptists orginally came from Switzerland and were welcomed to Pennsylvania by William Penn and his descendents.
Although Lancaster county thrives on tourism, the Amish community does not particularly like visitors, tourists, or sightseers. They are generally an intensely private religious community doing their best to go about living according to the ways of their religion and culture, and very much wish to be left alone unless you are invited. Don't take photos without permission, or harass or otherwise pester them about their way of living. Above all else, don't trespass on private property.
There are official tourist exhibits set up by the local government and various private enterprises that will allow you to learn about the county and the Amish in a way that is respectful and positive for everyone involved.
