Baie de Somme Picardie maritime, Regional natural park in Hauts-de-France, France.

The Parc naturel régional Baie de Somme - Picardie maritime covers about 135,000 hectares around Abbeville, crossed by the last 35 km of the Somme before its estuary between Le Crotoy and Saint-Valery-sur-Somme. Its landscapes run from the Côte Picarde, with shingle and sand beaches, dunes and chalk cliffs at its southern end, to the drained Marquenterre polder, the dry Vimeu plateau and the wooded Somme valley.

The area received the status of a regional park in 2020 in recognition of its exceptional environmental features. This official designation followed an assessment by national nature protection experts and was designed to ensure balance between human use and conservation.

The park's territory corresponds roughly to the former county of Ponthieu. In the Somme valley, former peat bogs are now used for hunting and fishing, while the Vimeu plateau around Friville-Escarbotin and Feuquières-en-Vimeu remains industrial, linked to its metalworking past. The Marquenterre, land reclaimed from the sea since the 13th century, is fed by the Maye and Dien rivers.

The Maison du Parc, the park authority's headquarters, is in Abbeville at the centre of the territory; the park stretches about 35 km along the Somme below the city, between Le Crotoy to the north and Saint-Valery-sur-Somme to the south. The Somme is navigable only through the parallel Canal de la Somme above Abbeville and the Canal Maritime d'Abbeville à Saint-Valery below it. The eastern hinterland beyond the A16 is farmland with few visitor facilities.

The park's territory corresponds roughly to the former County of Ponthieu. Its centreline is followed by the last 35 km of the Somme, which flows into the Channel between Le Crotoy and Saint-Valery-sur-Somme, forming the Réserve naturelle de la Baie de Somme. The Marquenterre, north of the valley, is land reclaimed from the sea and drained since the 13th century.