http://stackoverflow.com/questions/26863844/several-graphs-in-ggplot2-aesthetics-must-either-be-length-one-or-the-same-len
http://stackoverflow.com/questions/20057452/aesthetics-must-either-be-length-one-or-the-same-length-as-the-dataproblems

你先这样试下：
ggplot(data, aes(x = Region)) + geom_histogram()

你这个region是属于data的吧  感觉要这样的话也应该是data$region 或者直接x=region 因为你前面已经说明了data