Answer: Not necessarily the Amish.
Surprised? I sure was!
Turns out, that sometime during the 1970s, a faction of Hmong refugees found their way to Pennsylvania Dutch country after the war in their homeland left them homeless. The Mennonites of the Central Pennsylvania region--Mennonites are well known for opening their arms to assist refugees of all races and cultures--took them in, and were pleased to find that the Hmong were quite capable with a needle and thread. And the Mennonites, as you know, are rather closely affiliated with the Amish.
So, one thing led to another. In order to provide the Hmong with the opportunity to support themselves, they were permitted to use their skill to assist in the Amish quiltmaking industry. After a time, these families apparently made contact with family and friends back at home, and got them involved in the craft. Entire villages were transformed, as male and female, young and old alike, began sewing Amish quilts to send back to the States. The Hmong even moved the industry forward, by introducing their skill in applique work in the 1980s, a skill which the Amish did not possess.
As this phenomenon becomes more well known, shops which sell Amish quilts are becoming more vigilant as to whom they allow to stock their shelves with quilts. And rightfully so. While I greatly admire the industry, and how it has greatly improved the quality of life for the Hmong, I think I'd like to know that the $600 "authentic" Amish quilt that I am considering buying was not made by the Amish. The book shown above, World Of Amish Quilts, which comes very highly rated (by others; I have not had the opportunity to review it yet), has a beautiful "Trip Around the World" quilt on its cover.