| River setting for "The Wind in the Willows" | 53 |
| River Shannon's Lough ___ | 29 |
| River sight | 11 |
| River skipper | 13 |
| River source | 12 |
| River south of Kassel | 21 |
| River south of Minsk | 20 |
| River spanned by La Pont Neuf | 29 |
| River spanned by the Bagnell Dam | 32 |
| River spanned by the Brooklyn Bridge | 36 |
| River spanned by the Key Bridge | 31 |
| River spanned by the Pont Neuf | 30 |
| River spanned by the Ponte Vecchio | 34 |
| River spanned by the Three Gorges Dam | 37 |
| River spanner | 13 |
| River sport | 11 |
| River sporting activity | 23 |
| River starting in Switzerland | 29 |
| River stopper | 13 |
| River stoppers | 14 |
| River straddled by Basel, Switzerland | 37 |
| River straddled by Florence | 27 |
| River structure | 15 |
| River Styx V.I.P. | 17 |
| River surrounding Navy Island | 29 |
| River surrounding Notre Dame | 28 |
| River suspension | 16 |
| River target of the first Egyptian plague | 41 |
| River that "sweats oil and tar" in T. S. Eliot's "The Waste Land" | 89 |
| River that all travelers forget about after going down it | 57 |
| River that begins in Nord | 25 |
| River that begins in Pittsburgh | 31 |
| River that can be seen from the Uffizi Gallery | 46 |
| River that causes people to forget | 34 |
| River that crosses the border of Russia and Kazakhstan | 54 |
| River that divided the Romans and the Carthaginians | 51 |
| River that drains more than 20% of France | 41 |
| River that drains the Everglades into Biscayne Bay | 50 |
| River that drains the Lake of Thun | 34 |
| River that drains the western Pyrenees | 38 |
| River that empties into the Bering Sea | 38 |
| River that empties into the Caspian | 35 |
| River that empties into the Firth of Clyde | 42 |
| River that ends at Cairo | 24 |
| River that ends at Yuma | 23 |
| River that ends in Tarragona | 28 |
| River that feeds the Caspian Sea | 32 |
| River that feeds the Missouri | 29 |
| River that feeds the Ubangi | 27 |
| River that flooded Florence in 1966 | 35 |
| River that flows by the Hermitage | 33 |
| River that flows by the Hermitage Museum | 40 |
| River that flows into the Bay of Bengal | 39 |
| River that flows into the Seine | 31 |
| River that flows past four universities | 39 |
| River that flows past more than 40 castles | 42 |
| River that flows past Omaha | 27 |
| River that flows through Florence | 33 |
| River that flows through nine countries | 39 |
| River that flows through ten countries | 38 |
| River that flows to the Caspian Sea | 35 |
| River that forms at Pittsburgh | 30 |
| River that forms Lake of the Ozarks | 35 |
| River that forms part of Colombia's border | 46 |
| River that forms the Livingstone Falls | 38 |
| River that goes from calm to choppy? | 36 |
| River that joins the Fulda | 26 |
| River that joins the Mississippi | 32 |
| River that joins the Neisse | 27 |
| River that joins the Seine | 26 |
| River that joins the Severn | 27 |
| River that Kazakhs call Zhayyq | 30 |
| River that lends its name to an Austrian city | 45 |
| River that meets the Thames at London | 37 |
| River that named Iberia | 23 |
| River that once formed the western border of the Holy Roman Empire | 66 |
| River that passes by Essen, Germany | 35 |
| River that passes by the Hermitage | 34 |
| River that passes through Essen, Germany | 40 |
| River that rises in Cantabria | 29 |
| River that rises in Lake Tana | 29 |
| River that rises in Monte Falterona | 35 |
| River that rises in the Apennines | 33 |
| River that rises in the Ardennes | 32 |
| River that rises in the Bernese Alps | 36 |
| River that rises in the Vogesen Mountains | 41 |
| River that runs by 11 of the 20 largest cities in Russia | 56 |
| River that runs by the Uffizi | 29 |
| River that runs near the Leaning Tower of Pisa | 46 |
| River that runs near the Louvre | 31 |
| River that runs through York | 28 |
| River that Sherlock Holmes fell into | 36 |
| River that sounds like a horse | 30 |
| River that sounds muddy | 23 |
| River that starts at Pittsburgh | 31 |
| River that starts at the Vioménil | 36 |
| River that starts in the Graian Alps | 36 |
| River that starts in the Swiss Alps | 35 |
| River that the Burma Railway crosses | 36 |
| River that the dead drank from, in myth | 39 |