The Amish, a Christian denomination and a three-century-old ethnic group of German migrants known for its strict lifestyle standards, are one of the fastest-growing minority populations in the U.S. For more than a century, the number of Amish people—whose American lineage traces back to Pennsylvania in the early 1700s and the Midwest by the mid-1800s—has grown rapidly, from several thousand in 1910 to 250,000 a century later.
This population is easy to overlook, but its demographic shifts could reshape economic development, land use, health and public services in rural communities, according to Cory Anderson, a postdoctoral researcher at the Population Research Institute at Penn State.

Didn’t Amish break away from the Mennonites?
Hi Michael,
Yes! You are correct!
The sequence is:
Anabaptists (1520s) → Mennonites (1530s) → Amish (1693)
The Anabaptist movement began during the Protestant Reformation in the 1520s. Menno Simons (1496–1561), a former Catholic priest, became an influential Anabaptist leader, and his followers eventually became known as Mennonites.
Then in 1693, more than a century after Menno Simons, a Swiss Anabaptist/Mennonite minister named Jakob Ammann came into conflict with other leaders and broke off into the Amish.