is a small river in Arauco Province
, Biobío Region
. It has its main source in the hill of la Piedra, South of the Heights of Purgatorio in the Nahuelbuta Range
of the town of Santa Juana
, and it runs to the Northwest to empty into the Bay of Arauco
north of Arauco, Chile
. In its upper half it receives several streams from the forests of the Nahuelbuta Range that flow shortly after into a lower section that traverses a fertile and open valley, in which the fort of Old Arauco
existed, and the town of this name that was on the north shore. Its main tributaries are the riachuelos
of Conumo and of Los Patos. In the lowest reach of the river it has about 12 to 14 kilometers that allows the navigation of small boats.
Originally its upper section was named in mapudungun Raghleuru, clay river, and in the lower section had its present name, that later became the name of the whole, a compound of coran, "to form people", and of pagui, "the lion".