What is largest region of Georgia called?

The largest region of Georgia is called Coastal Plain.

Explanation:

Georgia's largest countryside is that the Coastal Plain that covers just about 60 % of the entire state. In prehistoric periods, this space of what's currently Georgia was lined by ocean.

Ocean waves slowly damaged down hills and resulted in formation of different land forms as they proceeded inland. When the ocean retreated, it left a huge space of sedimentary rock, clay, sand, and different matter deposits in the region currently referred to as the coastal plain.

Nationwide, the plain on the coast extends from Massachusetts to Gulf of Mexico, and which is up to 200 miles inside. Because of the result of the prehistoric ocean, the coastal plain is comparatively flat, with low relief has flat to mild slopes.

Answer: Coastal Plain