| River source | River South Esk | River South Esk, Angus |
| River South Tyne | River Sow | River Sow Navigation |
| River Sowe | River Spean | River Spen |
| River Spercheius | River Spey | River Spey Insh Marshes |
| River Spirit | River Spirits of the Anacostia | River Spodden |
| River Spree | River Springs | River Springs Elementary School |
| River Sprint | River St. Lawrence | River stage |
| River Stage, Brisbane | River States Athletic Conference | River States Conference |
| River Station | River station | River Station (Los Angeles) |
| River Station (Peoria, Illinois) | River steamboat | River Steeping |
| River Steyr | River Sticks | River Stiffkey |
| River Stinchar | River stingray | River Stirone |
| River Stix | River stone carp | River Stort |
| River stort | River Stour | River Stour (disambiguation) |
| River Stour (Dorset) | River Stour (Essex) | River Stour (Kent) |
| River Stour (Suffolk) | River Stour (Warwickshire) | River Stour (Worcestershire) |
| River Stour Navigation Act 1705 | River Stour Navigation Act 1781 | River Stour Trust |
| River Stour, Dorset | River Stour, Essex | River Stour, Kent |
| River Stour, Suffolk | River Stour, Warwickshire | River Stour, Worcestershire |
| River Stower Navigation Act 1705 | River Stower Navigation Act 1781 | River straightening |
| River Strat | River Strath Sgitheach | River Street |
| River Street (disambiguation) | River Street (Erie Railroad station) | River Street (film) |
| River Street (NJT station) | River Street (Savannah, Georgia) | River Street Bridge |
| River Street Bridge (Charles River) | River Street Bridge (disambiguation) | River Street Bridge (Iowa Falls, Iowa) |
| River Street Bridge (Marble Rock, Iowa) | River Street Firehouse | River Street Historic District |
| River Street Historic District (Connecticut) | River Street Historic District (disambiguation) | River Street Historic District (New Haven, Connecticut) |
| River Street Historic District (Troy, New York) | River Street Historic District (Wilkes-Barre, Pennsylvania) | River Street Inn |
| River Street station (Erie Railroad) | River Street station (New York, Susquehanna and Western Railroad) | River Street Streetcar |
| River Street streetcar | River Street Tower | River Street, Hackensack |
| River Street, Paterson station | River Strine | River Strule |
| River Stryi | River Strymon | River Styles Framework |
| River Styr | River Styx | River styx |
| River Styx (disambiguation) | River Styx (Dungeons & Dragons) | River Styx (Georgia) |
| River Styx (Gratiot County, Michigan) | River Styx (magazine) | River Styx (Marquette County, Michigan) |
| River Styx (Michigan) | River Styx (painting) | River Styx archaeological site |
| River Styx Magazine | River Styx, Ohio | River Subaya |
| River Subdivision | River Subdivision (Canadian Pacific Railway) | River Subdivision (CSX Transportation) |
| River Subdivision (CSX) | River Subdivision (disambiguation) | River Suck |
| River Suir | River Suir Bridge | River Suir navigation |
| River Suir Navigation | River Suite for Two Guitars | River Sulby |
| River Sullane | River surfing | River Surma |
| River Sutla | River Sutlaj | River Sutlej |
| River Sutlej (Hong Kong) | River Sutluj | River sutra |
| River Svalia | River Svir | River Swale |
| River Swan | River Swarbourn | River Swat |
| River Swere | River Swift | River Swilgate |
| River Swilly | River Swimming | River Swincombe |
| River Swine | River Syfynwy | River Syst |
| River Syst. | River system | River systems |
| River Systems | River systems of Thailand | River Systems of Thailand |
| River Syvaeri | River Syvari | River Syväri |
| River Syyvaeri | River Syyvari | River Syyväri |
| River Taedong | River Taf | River Taff |
| River Tagus | River Tagus. | River Tajo |
| River Tale | River Tales | River Tall |
| River Tam | River tam | River Tam (Firefly character) |
| River Tam session | River tam sessions | River Tamar |
| River Tame | River Tame (disambiguation) | River Tame (West Midlands) |
| River Tame (Yorkshire) | River Tame, Greater Manchester | River Tame, Staffordshire |
| River Tame, Warwickshire | River Tame, West Midlands | River Tame, Yorkshire |
| River Tana | River Tana, Kenya | River Tanana |
| River Tanat | River Tapi | River Tapti |
| River Tar | River Tara | River Tarcoles |
| River Tarell | River Tarff | River Tarff (Fort Augustus) |
| River Tarff, Fort Augustus | River Tarim | River Tarn |
| River taro | River Taro | River Tarrant |
| River Tas | River Tasso | River Tat |
| River Tauber | River Tavy | River Taw |
| River Tawd | River Tawe | River Tawe barrage |
| River Tawi | River Tay | River Tárcoles |
| River Tâf | River Têt | River Túria |
| River Team | River Tean | River teatree |
| River Tees | River Tees’s Valley | River Teesta |
| River Teeth | River Teifi | River Teign |
| River teiid | River Teise | River Teith |
| River Tekezé | River Teme | River Ter |
| River Ter SSSI | River terminus | River Tern |
| River tern | River Tern (bird) | River tern (bird) |
| River terrace | River Terrace | River Terrace (Washington, D.C.) |
| River Terrace Apartments | River Terrace School | River Terrace, DC |
| River Terrace, Washington, D C | River Terrace, Washington, D. C. | River Terrace, Washington, D.C. |
| River Terrace, Washington, DC | River terraces (tectonic-climatic interaction) | River terraces (tectonic–climatic interaction) |
| River terraces, tectonics, and climate change | River terrapin | River terrapin (disambiguation) |
| River Terrig | River Tescou | River Teshio |
| River Test | River Tet | River Teviot |
| River Thame | River Thames | River thames |
| River Thames (disambiguation) | River Thames Barge Builders Trade Union | River Thames Barge Builders Trades Union |
| River Thames Barge Builders Union | River Thames Catchment Board | River Thames Frost Fair |
| River Thames frost fair | River Thames frost fairs | River Thames whale |
| River Thames Whale | River Thames, Ontario | River Thaw |
| River Thet | River Thjorsa | River Thon |
| River Thouet | River Thrushel | River Thurne |
| River Thurso | River Thyamis | River Tib |
| River Tiber | River Tiber (band) | River Tiber (musician) |
| River Ticino | River Tiddy | River Tien |
| River Tiffey | River Tigris | River Tigris (constellation) |
| River Till | River Till (disambiguation) | River Till (Wiltshire) |
| River Till SSSI, Wiltshire | River Till, Lincolnshire | River Till, Northumberland |
| River Till, Wiltshire | River Tillard, Nova Scotia | River Tillingbourne |
| River Tillingham | River Tilt | River Timavo |
