Answer:
As British people consider the British Received pronounciation (RP) the standard pronounciation of British English, people in North America consider General American (GA) the accent which is more difficult to distinct as belonging to a particular area.
The accent is not only present in the United States but it's also common in several parts of Canada.
The General America accent is mostly similar to a generalized Midwestern accent.
Many newscatsers and politicians attend accent-reduction classes in order to eliminate or reduce the regional features from their speech patterns.