Does United States have Dragon Boat Festival?
Not observed here
There is no Duanwu in the United States, but there are dragon boat races — a good many. What happened here is that the boats arrived and the calendar did not: the races are run as summer sport and city festivals, with dates picked by organisers for a convenient weekend and no relation to the fifth day of the fifth lunar month. The eleven federal holidays are all fixed dates or nth Mondays, none of them following the moon, so the festival has no institutional peg to hang from.
What is this topic?
The fifth day of the fifth lunar month is a public holiday in both Taiwan and mainland China, while Japan moved the same 'fifth of the fifth' onto the Gregorian calendar and turned it into a statutory children's day. This page compares four things: who gets the day off, where the rice dumplings and the boats sit, how far local versions are listed as heritage in their own right, and how the day was re-defined in Japan as respecting a child's character while also thanking the mother.
Sources and dates
Dates follow local time zones, calendars, and official notices. Check the source when a date is estimated or locally variable.