where does the river thames start and end

The River Thames starts at Thames Head in Gloucestershire, England, and ends at the Thames Estuary where it meets the North Sea. Commonly accepted as the longest river entirely in England, it stretches about 346 km (215 miles) eastward through scenic countryside and bustling cities.

Traditional Source

Thames Head, near Kemble in the Cotswolds (grid reference ST980994), is widely recognized as the official start, about 1.5 miles north of Kemble village. This spot lies in southern Gloucestershire, close to Cirencester, amid rolling hills perfect for a historical pilgrimage—imagine Victorian explorers debating the exact spring amid wildflowers. Some sources note Seven Springs (near Cheltenham) as an alternative, where the River Churn rises, extending the length by 14 miles since it's farther from the sea.

Path Highlights

The Thames meanders through charming towns:

• Oxford (locally called the Isis)
• Reading
• Henley-on-Thames
• Windsor
• Central London (draining all of Greater London)

This journey blends rural idylls with urban energy, powering history from medieval castles to modern commerce.

Estuary and End

It becomes tidal below Teddington Lock, widening into the Thames Estuary between Essex (near Tilbury) and Kent (near Gravesend), finally merging with the North Sea at Southend-on-Sea. Here, it supports massive ports and wildlife, a dynamic finale to its epic flow.

Aspect| Details
---|---
Length| 346 km (longest fully in England, 2nd in UK) 39
Source| Thames Head, Gloucestershire (or Seven Springs alt.) 1
Mouth| Thames Estuary/North Sea, Southend-on-Sea 35
Key Cities| Oxford, Reading, Windsor, London 17

TL;DR: Thames Head to Thames Estuary—a watery lifeline through England's heart. Information gathered from public forums or data available on the internet and portrayed here.