Morsang-sur-Seine (French pronunciation: [mɔʁsɑ̃ syʁ sɛn] ⓘ, literally Morsang on Seine) is a commune in the Essonne department in Île-de-France in northern France.

Although at least 40 kilometers from Paris, by a wise policy planning, it has preserved its original charm and offers quiet and residential comfort.

Morsang-sur-Seine, situated in Île-de-France, benefit from an oceanic climate fresh winters and soft summer, with regular precipitation on the whole year.

The slightest urban population density explains a constant negative difference from two to three degrees raised(found) between Auvernaux and Paris.

The period of sunshine adding up 1 798 hours is comparable to all the regions in the North of the Loire but lesser than in the North of the department by the frequent presence of tablecloth of mist near the Seine, fields and vast forests.