if you are interested in being a tour guide in the United States, you might be required to earn professional licensing, depending on which city or area you want to work in. If you plan on being a guide in any of the following cities, you will need to get licensed first:
Washington, D.C.
New York, NY
Savannah, GA
Charleston, SC
Gettysburg Battlefield, PA
Vicksburg Battlefield, MI
New Orleans, LA
If you want to be a tour guide in New York City, you have to pass the Professional Licensing Examination for New York City Sightseeing Guides. The test consists of 150 questions, and you need to answer 97 correctly. The questions cover topics such as New York transportation, history and architectural landmarks.
Becoming a tour guide in Washington D.C. requires submitting an application, which includes completion of the Professional Sightseeing Tour Guide Examination. You'll also need to be able to communicate in English and have a clear criminal history over the last five years.
Source: learn.org