Which U.S. marine sanctuary contains the northernmost coral reefs in the United States?

Flower Garden Banks National Marine Sanctuary contains the northernmost coral reefs in the United States.

The sanctuary lies in the northwestern Gulf of Mexico, about 100 nautical miles from Galveston, Texas. Its coral communities grow on underwater banks created when ancient salt domes pushed the seafloor upward. That unusual geology places substantial coral reefs far north of the Caribbean’s better-known reef areas.

When the sanctuary was designated in 1992, it included East Flower Garden Bank and West Flower Garden Bank. Stetson Bank was added in 1996, and a major expansion in 2021 brought 14 additional reefs and banks under protection. The sanctuary now covers roughly 160 square miles.

The reefs support more than 20 coral species and nearly 300 fish species, along with sponges, crustaceans, sea turtles, manta rays and other marine life. A common mistake is choosing Florida Keys National Marine Sanctuary simply because Florida is famous for U.S. coral reefs. The Florida Keys have extensive reefs, but Flower Garden Banks holds the distinction for the country’s northernmost coral reefs. The name refers to the banks’ colorful underwater appearance, not to islands or exposed land.