St. Augustine, Florida, is the oldest US city and the oldest military outpost in the continental US (Puerto Rico is a US territory and was colonized earlier). In 1565, Pedro Menendez made friends with some tribes in Florida and the colony could have had feasts which included natives, but should a feast at a military outpost count as the first Thanksgiving. Technically, the French Huguenots were the first to make friends with the natives, but the colony was often at the point of starvation, so the act of feast is within doubt. The Spanish had committed many atrocities before any act of peace was broached, so you should consider that before giving Spanish Florida credit for establishing the first Thanksgiving. Read how the Spanish wiped out the Taino in Peurto Rico and ask whether even that territory deserves that award.
My Spanish family was here in Florida, before the Pilgrims, so the only thing that’s for sure is that Thanksgiving belongs to my family, in either case. I also have Huguenot ancestry, but I can’t truly claim one of those ancestors came to Florida, but there’s a slight chance. I also have Jamestown ancestors, so I’ve got that thanksgiving covered, too. I also have Native American ancestry, I’m doubly covered. Catholics seem to want a piece of Thanksgiving and want to claim Miles Standish, but I doubt he died Catholic and I’ sure he didn’t get a Catholic Last Rites. Reason for yourself whether Spanish Florida owns the first Thanksgiving, but a military outpost doesn’t get my vote. The Pilgrims consisted of families and Standish was the only soldier–and Thanksgiving is about families so I favour the Pilgrims; though, I had family in Spanish Florida, too.