Which state has the longest border on the gulf of mexico?

Florida

Explanation:

Of the five states – Florida, Louisiana, Texas, Alabama and Mississippi – having a shoreline on the Gulf of Mexico, Florida has the longest border or shoreline measuring 770 miles (approximately 1239 kilometres). The total length of the Gulf of Mexico's coastline is 1631 miles (approximately 2625 kilometres). With this data it can be deduced that Florida has 47.2% of the Gulf of Mexico’s coastline.