An American History major is really just a specialized version of a regular history major. In practice, if you decide to major in American History, you'll take several American History courses but you'll also be required to take a wide variety of other kinds of history courses within the larger department.
No matter how thrilling (or dull) your high school American History and Civics classes have been, we can pretty much guarantee that American History courses in college will be a lot more exciting. You won't have to memorize a bunch of names and dates. No, there will be few - if any - matching quizzes in college-level history courses. Instead, you'll pursue major developments in American foreign policy from colonial times to the present; analyze the unique and fascinating contributions of the American West to the evolution of the United States; and discuss Jacksonian Democracy, Reconstruction, Progressivism, American Imperialism, and many other -isms.
Yeah, but can you get a job with a major in American History? Absolutely. If you major in American History, you'll learn how to think clearly and critically, to write clearly and convincingly, and to read intelligently. These are exactly the things all employers want.