About 12.5 miles. Took us 4 hours of relaxed paddling (a lot of time, just floating being carried by the current). There are some tubing businesses that use this section of the river. There are frequent sections with faster water (not sure I can call them rapids).
Beautiful trip. Saw fish, deer, bald eagles.
River access in Zumbro Falls was excellent and as described. In Millville, we found we had to exit at the bridge. The place on this map, Reads Park is now charging. If you stop under the bridge on the right side of the river, there is a mowed path up to the road. This is a good alternative.
Safety Notes
This is a pretty enjoyable and relaxed river.
Gear Notes
1 fiberglass kayak and 3 inflatable kayaks
Conditions
The majority of the river was pretty shallow. We had to choose our path so that we didn't hit bottom.
