One problem with retrieving census data is that the first Muslims in the New World (I'm not entirely clear on how you're defining "America," so I'll start there) were slaves. We know, for instance, that there were mariscos - or hidden converts from Islam - among Columbus' crew, such as Pedro Alonso Nino, meaning that Muslims have been in the Americas for as long as the Spanish have. Equally, as this article says, the first Muslims who came en masse were slaves, brought in to work on Spanish and other European plantations. Plantation owners in Louisiana would specifically request Muslim slaves as they came from areas that grew the crops that were growing in popularity in Louisiana. As the number of slaves in the Americas grew, so did the number of Muslims, and we can see records of them in death records, sales records, and even their own writings.

Slaves weren't the only Muslims coming into the Americas either. Anthony Janszoon van Salee was a Dutch settler who settled in New Holland, became prosperous, and was clearly and unambiguously Muslim.

While the majority of Muslims in America were slaves, that doesn't mean it wasn't there. Islam has been in the US for as long as Europeans have been here.