the one in Virginia is located in Williamsburg, known as the Robertson Windmill.
the one in Illinois is in Batavia and known as a Dutch windmill
the Massachusetts one is a Cape Cod windmill in Eastham
the Rhode Island one is based on an Old Windmill in Portsmouth
and the Texas one shows windmills typical of the southwest
I was sure I had a couple more s, but alas I can't find them. At least I have the complete set of stamps.
wind your way to Sunday Stamps for windmills or lighthouses