Final answer:
The largest international tourist source for the USA includes travelers from Europe and Asia, with foreign tourists significantly impacting the U.S. economy, especially in major destinations like New York, Florida, and California.
Step-by-step explanation:
The largest international tourist source for the USA are travelers from various parts of the world. When discussing tourists, anyone who spends more than 24 hours in a location outside their hometown is generally considered a tourist. International tourists have a significant economic impact on the United States and tend to spend a considerable amount of money in the country, especially in popular destinations such as New York, Florida, and California. While the exact largest source of international tourists to the USA can vary over time, historically, countries from Europe and increasingly from Asia have been significant sources of tourists. It's important to note that international tourism patterns can shift due to various factors such as political relationships, economic conditions, and travel restrictions, as seen with the anticipation of increased tourism from the United States to Cuba.