Hi there !
By coincedence I found your message on this board here and found it very interesting to see that also people in the US are having the same name as I have.
My grandpa, Heinrich Wilhelm Gruenkemeier ( but written with the Umlaut "u" ) came from a small town in the mentioned area. The town is called Hilter.
Please contact me to see what else matches.
Uwe Grünkemeier, Kaarst, Germany