Seine

• Published Seine course · ≈773 km

  Agence de l’eau Seine-Normandie overview: Source-Seine on the Langres plateau to the English Channel between Le Havre and Honfleur. Other agency material reports 777 km; this print uses the internally consistent overview definition.

• Seine river catchment · ≈75,000 km²

  Seine river catchment in the agency overview; distinct from the 94,500 km² Seine-Normandie administrative basin. Other agency material reports 77,000 km²; not an area calculated from the map.

• Source altitude, agency overview · 450 m

  Published source altitude at Source-Seine on the Langres plateau, according to the Seine-Normandie agency overview. This is a contextual published altitude, not elevation sampled from the drawn line.

• Yonne · Marne · Oise · 3

  Three principal tributaries named by the agency overview: Yonne, Marne and Oise. This is not a count of all tributaries; the map also retains surrounding source watercourses.

• Origin → estuary outlet · Source-Seine → English Channel

  Source-Seine on the Langres plateau to the Channel between Le Havre and Honfleur.

• Agence de l’eau Seine-Normandie
• Facts: Agence de l’eau Seine-Normandie (overview) · Map: IGN / OFB / Sandre, BD TOPAGE 2022, Licence Ouverte 2.0; selected and adapted · Context: Natural Earth
• Licence Ouverte 2.0

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

Visual guidance · Paper proof pending.