The Savanna State Forest is located in Aitkin and Saint Louis counties in the U.S. State of Minnesota. Comprising over 238,000 acres, the forest is bisected by the Upper Mississippi River, and contains Savanna Portage State Park, which preserves a historic trade route connecting the Mississippi River with upper reaches of the Saint Lawrence River draiā¦The Savanna State Forest is located in Aitkin and Saint Louis counties in the U.S. State of Minnesota. Comprising over 238,000 acres, the forest is bisected by the Upper Mississippi River, and contains Savanna Portage State Park, which preserves a historic trade route connecting the Mississippi River with upper reaches of the Saint Lawrence River drainage basin.