The Amish ( ) are members of an Anabaptist Christian denomination, best known for simple living, plain dress and resisting modern conveniences. The roots of the Amish began in Switzerland among Swiss Brethren in 1693 under the leadership of Jakob Ammann. Then, in the early 18th century they began immigrating to Pennsylvania because of intense persecution. Today, they continue to speak the Pennsylvania German or Alemannic German of their former homeland. Over the years, there have been several divisions among the Amish. The Old Order Amish are those that have been the most successful at resisting change and in retaining their traditional way of life. As of 2000, over 165,000 Old Order Amish live in Canada and the United States. A new study in 2008 suggests their numbers have increased to 227,000. No Amish remain in Europe.

Amish church membership begins with baptism, usually between the ages of 18 and 21. It is a requirement for marriage, and once a person has 'joined church', they must marry within the faith. Church districts average between 20 to 40 families, and worship services are held every other Sunday in a member's home. The district is led by a bishop and several ministers and deacons.

The rules of the church — the Ordnung — must be observed by every member. These rules cover most aspects of day-to-day living, such as no power-line electricity, limiting the use of telephones, prohibition of ownership and operation of an automobile, and specifying the style of dress. Amish do not buy insurance nor accept government assistance, such as Social Security. As Anabaptists, Amish practice nonresistance and will not perform any type of military service. Members who do not conform to these expectations and who cannot be convinced to repent, are excommunicated. In addition to excommunication, members may be shunned — a practice that limits social contacts in order to shame the wayward member into returning to the church. Teenagers in many ordnungs, who are not baptized are not bound by the rules. They go through a period of rumspringa, or running around, often with a certain amount of misbehavior that would otherwise not be tolerated. Not all ordnungs, particularly in the Old Order world, practice this custom.

The Amish seek to limit contact with the outside world; instead, they emphasize church and family relationships. They typically operate their own one-room schools, and stop their education at grade eight. They value a rural life, where a large family provides an abundance of manual labor. Because of intermarriage among this relatively small population, higher incidences of certain inheritable diseases occur. Their traditional way of living also makes them an object of tourism, and this has caused many clashes with the modern world.

Population and distribution

The geographic and social isolation of Amish communities make it difficult to determine the total Amish population. Rough estimates by various studies have estimated their numbers at 123,000 in 1992, 166,000 in 2000, and 227,000 in 2008, for a growth rate of nearly 4% per year. In 2000, approximately 165,620 Old Order Amish resided in the United States, of which 73,609 were church members. The Amish are among the fastest-growing populations in the world, with an average of 6.8 children per family. Old Order Amish groups include the Byler group, Nebraska Amish in Mifflin County, Pennsylvania, the Reno group, and the Swartzentruber Amish in Holmes County, Ohio.