What river is mentioned as draining into the Atlantic Ocean in the eastern part of a particular state?

The Savannah River drains into the Atlantic Ocean, making it a significant waterway for the eastern part of Georgia. This river serves as a natural boundary between Georgia and South Carolina and flows southeastward into the ocean near the city of Savannah. Its strategic location contributed to the development of the city as an important port, facilitating trade and transportation.

In this context, the other rivers listed do not drain into the Atlantic Ocean in that region. The Mississippi River flows into the Gulf of Mexico, the Ohio River is a tributary of the Mississippi, and the Rio Grande primarily flows between the United States and Mexico, draining into the Gulf of Mexico as well. Therefore, the Savannah River is the correct answer, as it is specifically associated with draining into the Atlantic Ocean in the eastern United States, particularly relevant to the geography of Georgia.