https://www.uspto.gov/sites/default/files/documents/BasicFac...
Page 11
> Is federal registration of my mark required?
> No. In the United States, parties are not required to register their marks to obtain protectable rights. You can establish "common law" rights in a mark based solely on use of the mark in commerce, without a registration.
I have read that the US is also "first use" and not "first to file", eliminating a race to registration.