Liernu is a subdivision of the Walloon municipality of Éghezée, located in the Belgian province of Namur.
Liernu is best known for its centuries old Big Oak Tree (50°35′03″N 4°49′40″E / 50.584206°N 4.827799°E), one of the largest and oldest in continental Europe.
Liernu had 806 inhabitants as of March 2006, and extends over 625 hectares (1,540 acres).
Coordinates: 50°35′03″N 4°49′50″E / 50.584183°N 4.830536°E