Thames

• Source-to-sea length · ≈346 km

  Published full-course estimate, 215 miles; not Thames Path length and not a sum of artwork segments.

• Drainage upstream of Teddington · ≈10,000 km²

  Environment Agency says the catchment draining to Teddington approaches 10,000 km². This excludes drainage entering farther downstream and is not the Thames River Basin District.

• EA Thames lock / weir complexes · 44

  44 Environment Agency-owned lock and weir complexes along the non-tidal Thames. EA separately lists one on the River Kennet at Reading. Not a claim that there are only 44 locks in the wider river system.

• Non-tidal navigable river · ≈218 km

  Environment Agency overview publishes 135 miles of navigable non-tidal River Thames; multiplied by 1.609344 and rounded to the nearest kilometre. Not whole source-to-sea length or Thames Path trail length.

• Origin → estuary outlet · Gloucestershire → North Sea

  A field near Kemble, Gloucestershire, to the North Sea through the Thames estuary.

• River Thames Society
• University of Greenwich, Greenwich Maritime Centre
• Environment Agency, Thames Region
• Environment Agency
• Facts: River Thames Society / Greenwich / Environment Agency · Contains OS data © Crown copyright and database right 2026 (OS Open Rivers 2026-04, OGL) · Context: Natural Earth
• Open Government Licence

Decorative artwork, not a navigation chart. Mapped shorelines and extents are approximate; historical or modeled data are labeled.

Visual guidance · Paper proof pending.