Well, since a good proportion of African Slaves brought to the USA were followers of Islam, I’d imagine it has been celebrated by some in the USA for at least a hundred or more years. There were also Moors here long before the USA became the USA - they mostly migrated out of Spain where they were essentially persecuted and expelled. So at least as long as US Federal Employees have celebrated Christmas, which became a federal employee holiday in 1870.
The very label “US Holiday” is whatever anyone in the USA chooses to call it. If a US Citizen celebrates it, it is a “US Holiday” to them. There are zero official US National Holidays in this country - not one. Anyone, Apple Inc. included, can create a subscription calendar with whatever events they wish to include.
You can read a little bit about the more commonly observed Holidays in the USA at https://www.timeanddate.com/holidays/us/