We tended to plan the day around lockages–two in a day was plenty, though once we managed three. We hopscotched our way down from Minnesota to Wisconsin, above Prairie du Chien, in seven days. Weekends, the river was sometimes busy with pleasure craft, houseboats full of young people clad in bikinis and deep tans, looking like a set from a Gidget movie.  But during the week, we often had whole stretches to ourselves.

Most of the boaters we met had high-powered fiberglass cruisers. They waved as they roared past (much waving on the river) and left the Leah rocking helplessly in their wakes. We learned to take them across our bow. Once we had to wait at a lock while the paddle-wheel steamboat Delta Queen, looking like a huge apartment house, was locked through, her calliope maniacally churning out “Alexander’s Ragtime Band.” The barges in the their linked rows were the kings of the river, the pilots telling us over the radio, in their silky Southern voices, on which side they wanted to pass.

From Prescott, Wis., our first stop, all the way to Prairie du Chien, the marinas where we rented a slip each night proved to be worlds of their own, transient communities with the easy friendliness of campgrounds. At Prescott, the marina owner gave us a bag of charcoal so we could use the grill in the little town park pitched above the river. I stood on the grassy rise, glass of chardonnay in hand, turning the chicken, gazing out at the confluence, where the deep blue ribbon of the St. Croix River cuts in the golden brown of the Mississippi. Next to the grill, a bronze plaque marked the place: ‘In 1680 explorers Hennepin and DuLhut both passed this point.”