Morcenx (French pronunciation: [mɔʁ.sɛ̃ks]; Gascon: Morcens) is a former commune in the Landes department in Nouvelle-Aquitaine in southwestern France. On 1 January 2019, it was merged into the new commune Morcenx-la-Nouvelle.

Morcenx is situated in the Grande Lande in the Landes forest (forêt des Landes) on the Bez. It is accessed by the A63 motorway, exit 14 for Onesse-et-Laharie.

The Morcenx area, bordered by the Bez and its tributaries, seems to have been occupied since prehistoric times. Flint tools, domestic furniture, and a cinerary (cremation ashes) box from the 1st Iron Age have been found there.

The church Saint Pierre de Morcencz was mentioned in the Liber rubeus in the 12th century.

Historical population

Year Pop. ±% 1793 645 —     1806 678 +5.1% 1821 714 +5.3% 1831 811 +13.6% 1841 795 −2.0% 1851 919 +15.6% 1861 1,321 +43.7% 1872 1,718 +30.1% 1881 2,049 +19.3% 1891 2,193 +7.0% 1901 2,230 +1.7% 1911 2,663 +19.4%

Year Pop. ±% 1921 2,768 +3.9% 1931 3,208 +15.9% 1946 3,033 −5.5% 1954 3,013 −0.7% 1962 4,166 +38.3% 1968 5,305 +27.3% 1975 5,690 +7.3% 1982 5,406 −5.0% 1990 4,332 −19.9% 1999 4,383 +1.2% 2008 4,600 +5.0% 2013 4,447 −3.3%

• Communes of the Landes department