How to get all retweets within certain area like U.S



i need to get all retweets within U.S. But I am not sure how to do that. The location filter does not check on status.getRetweetedStatus.getGeoLocation.I also can get all retweets and filter out location by myself. But how to get all retweets? It seems the “RT” search does not work on retweet text either.