Retalhuleu is a depairtment locatit in the sooth-wast o Guatemala, extendin frae the muntains tae the Paceefic Ocean coast. It haes an aurie o 1856 km². In 2002 the population o the Depairtment o Retalhuleu wis 241,411. The caipital is the ceety o Retalhuleu.
The lairgest Native American group in the state is the K'iche' (Quiché) Maya fowk. The depairtment contains a number o Pre-Columbie ruins, includin Takalik Abaj an San Juan Noj.
The Depairtment is dividit intae nine municipalities: