I'm not sure if this is the right place to post this. I would like to read some works on american history written by an outside source.
Not strictly a history work, but Alexis de Tocqueville wrote "Democracy in America" which is used now as a history of American life circa early 1800s
British historians and journalists come to mind - Simon Schama, Alistair Cooke, Lewis Namier, etc. Karl Marx wrote about American slavery as well.
Paul Johnson, British, wrote "A History of the American People", which can be found here.
It's ambitious and interesting but not always convincing.