Original: Geography Nempont-Saint-Firmin is situated in the valley of the Authie river , the border with the department of the Somme , some 8 miles ( 13 km ) south of Montreuil-sur-Mer , on the N1 road .
Simplified: It is found in the region Nord-Pas-de-Calais in the Pas-de-Calais department in the north of France .