How many old windmills are still standing in the United States?

There are at least 12 historic Dutch windmills still standing in the United States as of 2016, according to DutchinAmerica.com. The windmills are concentrated in the upper Midwest, although there are several in California and one in New Jersey.

The Dutch mills were generally fabricated in the Netherlands and re-assembled on site in the United States during the late 19th century. An additional six million windmills and wind pumps were built in the United States from 1850 to 1970, but today most of those have been replaced by wind turbines. There is a partial list of known U.S.-built windmills at Wikipedia.com.