I've documented my family being Mennonite here in the US from at least the 1790's (potentially earlier) through to the early 1900's. A portion of the family moved away from Lancaster, heading west, to Wayne County, Ohio - another of the largest Amish and Mennonite communities. Based on research by other family members (though I've not worked quite far enough back to confirm with my own research), some of my ancestors may have been part of the Swiss Anabaptist movement in the late 1700's, arriving in the US as they fled religious persecution.
From the Mennonite Church USA site:
"Mennonites are Anabaptists...Anabaptism grew out of the 16th-century Radical Reformation (which followed the Protestant Reformation). Technically, Anabaptists are neither Catholic nor Protestant, although they do share some beliefs of both.The first Anabaptists separated from the state church when they began re-baptizing adults and refusing to baptize infants until they could make an adult decision to follow Christ. Anabaptism literally means to re-baptize."
If you ever find yourself researching someone who was Mennonite, here are some of the resources I've used. As with many churches, they have a wealth of genealogical material available. I've also added these to my Genealogy Toolbox for easy reference:
One thing I can say for sure, my 2nd great-grandfather (shown above on the left), Tobias Swinehart (1833-1911), had a pretty impressive beard! His sister-in-law, Esther (Homsher) Brown (1834-1927), my 2nd great-grand-aunt (shown to the right) was a member of the Mennonite Church until she passed away. You could look at either of these images and know in a heartbeat they were either Amish or Mennonite. As I move forward to more recent generations, I've not found anyone still in the Mennonite community. But I'm not ruling it out as a possibility! I still have much more research to do in this branch of my tree.