| River structure | 15 |
| River straddled by Florence | 27 |
| River straddled by Basel, Switzerland | 37 |
| River stoppers | 14 |
| River stopper | 13 |
| River starting in Switzerland | 29 |
| River sporting activity | 23 |
| River sport | 11 |
| River spanner | 13 |
| River spanned by the Three Gorges Dam | 37 |
| River spanned by the Ponte Vecchio | 34 |
| River spanned by the Pont Neuf | 30 |
| River spanned by the Key Bridge | 31 |
| River spanned by the Brooklyn Bridge | 36 |
| River spanned by the Bagnell Dam | 32 |
| River spanned by La Pont Neuf | 29 |
| River south of Minsk | 20 |
| River south of Kassel | 21 |
| River source | 12 |
| River skipper | 13 |
| River sight | 11 |
| River Shannon's Lough ___ | 29 |
| River setting for "The Wind in the Willows" | 53 |
| River setting | 13 |
| River separating Queens from the Bronx | 38 |
| River separating Ontario and Quebec | 35 |
| River separating Germany and Poland | 35 |
| River separating continents | 27 |
| River seen while "sur le pont d'Avignon" | 54 |
| River seen from Windsor Castle | 30 |
| River seen from the Eiffel Tower | 32 |
| River seen from Lorelei Rock | 28 |
| River seen from Ciudad BolÃvar | 33 |
| River seen from Bern | 20 |
| River sediment | 14 |
| River section | 13 |
| River sacred to over a billion | 30 |
| River runner | 12 |
| River rompers | 13 |
| River romper | 12 |
| River rodent | 12 |
| River rising through the Bernese Alps | 37 |
| River rising in Tibet | 21 |
| River rising in the Vosges Mountains on the border of Alsace-Lorraine | 69 |
| River rising in the Vosges Mountains | 36 |
| River rising in the Urals | 25 |
| River rising in the Rocky Mountains | 35 |
| River rising in the Grampians | 29 |
| River rising in the Carpathians | 31 |
| River rising in the Cantabrian Mountains | 40 |
| River rising in the Bernese Alps | 32 |
| River rising in the Ardennes Mountains | 38 |
| River rising in the Ardennes | 28 |
| River rising in Silesia | 23 |
| River rising in Mongolia | 24 |
| River rising in Bavaria | 23 |
| River restrainers | 17 |
| River residue | 13 |
| River resident | 14 |
| River rental | 12 |
| River regulators | 16 |
| River regulator | 15 |
| River reflection | 16 |
| River rat | 9 |
| River rapids | 12 |
| River rapid | 11 |
| River racer | 11 |
| River quay | 10 |
| River pronounced "waz" | 32 |
| River projects | 14 |
| River project evaluation? | 25 |
| River project | 13 |
| River probably discovered by Columbus in 1498 | 45 |
| River predator, briefly | 23 |
| River port NNW of Brisbane | 26 |
| River port east of Le Havre | 27 |
| River port | 10 |
| River pollution problem | 23 |
| River pollutant | 15 |
| River player | 12 |
| River plains named for their usual shape | 40 |
| River phenomenon | 16 |
| River phenomena (or what literally happens six times in this puzzle) | 68 |
| River People of the Southwest | 29 |
| River past Westminster Palace | 29 |
| River past Thebes | 17 |
| River past the ruins of Nineveh | 31 |
| River past St.-Germain | 22 |
| River past Solothurn | 20 |
| River past Orsk | 15 |
| River past Orenburg | 19 |
| River past Notre Dame | 21 |
| River past Memphis | 18 |
| River past Luxor | 16 |
| River past Logroño | 21 |
| River past Liechtenstein | 24 |
| River past Iola, Kansas | 23 |
| River past Interlaken | 21 |
| River past Grenoble | 19 |
| River past Geneva | 17 |