We put in at a boat ramp under the Highway 96 bridge just outside of Fort Valley, GA. The river was low during this trip so we encountered some shallow spots and submerged trees, but our Mad River Adventure 14' canoe easily made it through it all.
This is a very scenic river with several sandbars that are suitable for camping, fishing, swimming, and the like. After paddling a little ways on this part of the river you can find yourself in the middle of nowhere. I rarely see other canoes or kayaks. Some fallen trees keep power boats from going very far down river.
You can put in at the 96 ramp and take a day trip to a takeout in Marshallville, GA. However, I usually spend the afternoons going down river and then simply turn around. Except for a few spots, the river current is gentle enough to paddle against.
The nearest town is Fort Valley. Here you will find a few restaurants and gas stations if needed. However, major hotels and restaurant chains can be found about 25 minutes from the river in Warner Robins, GA.
No fees required.
The boat ramp is located a few miles west of Fort Valley, GA on Highway 96. There are no nearby distinguishing landmarks other than the river itself. So, look for the sign saying "Flint River" and there will be a side road leading to the ramp.
The boat ramp has ample places to park. There is no fee required for parking. I had left my truck here several times and have never had anything stolen or vandalized.