I have Manthey ancestors from the town of Dyck (which was destroyed in WW-II), but I believe it was in that area.
According to family legend, there were 6 grown children who left Germany in the late 1800's. Two went to Australia, two to Canada, and two went to the USA. My g-g-grandfather is one who went to USA, originally Milwaukee, Wisconsin, and then Muscatine, Iowa. Would be happy to share information with you.