New York was the epicentre of the COVID pandemic in the USA. Lack of urgency in isolating and locking down caused the spread across the country. The vast majority of cases came from domestic spread.
"“It means that we missed the boat early on, and the vast majority in this country is coming from domestic spread,” said Kristian Andersen, a professor in the department of immunology and microbiology at Scripps Research. “I keep hearing that it’s somebody else’s fault. That’s not true. It’s not somebody else’s fault, it’s our own fault.”"
Travel From New York City Seeded Wave of U.S. Outbreaks - The New York Times