I personally believe America's thanksgiving should also be on this date, because Oktoberfest is happening, and that commemorates thanking God for a fine harvest.
Which came before the other the US Thanksgiving Day or Octoberfest? I suppose I could do a quick search but I thought you might know.
Our Thanksgiving was begun in the 1790's by George Washington. Oktoberfest did not come about until 1810. But in England, up until the Reformation, there was a day set aside to thank God for His blessings.