Lunca Cernii de Jos (Hungarian: Alsónyiresfalva, German: Birkendorf) is a commune in Hunedoara County, Transylvania, Romania.

It is composed of eight villages: Ciumița (Csumicapuszta), Fântâna (Vádtelep), Gura Bordului, Lunca Cernii de Jos, Lunca Cernii de Sus (Felsőnyiresfalva), Meria (Kékesfalva), Negoiu (Nyegojlunka), and Valea Babii.

Lunca Cernii de Jos is situated among the foothills of the Poiana Ruscă Mountains.

Lunca Cernii de Jos and Lunca Cernii de Sus lie for 11 km (6.8 mi) along the river valley; the local peasantry works in animal husbandry and logging.

Meria is located on a mountainside at over 1,000 m (3,300 ft) altitude, separated from other villages by high peaks, deep valleys and dense forest.