Final answer:
The first British fort in Georgia was Fort King George, built in 1721, predating the more prominent Fort Frederica, which was constructed in 1736.
Step-by-step explanation:
The name of the first British fort constructed in Georgia was Fort King George. Established in 1721, this fort served as an outpost at the mouth of the Altamaha River, marking a British presence deep within the contested frontier against the competing Spanish and French influences. Despite its significance, Fort King George was a tenuous hold due to harsh conditions, and most of the soldiers were eventually recalled, leaving only a skeleton crew to act as lookouts and warn of Spanish activities. Fort Frederica was built later, in 1736, and became known as the most important fortified outpost when Georgia was functioning as a buffer zone between British settlements and Spanish Florida.