Note: Do not rely on this information. It is very old.
UcayaliUcayali, a river of South America, rising in the Peruvian Andes as the Apurimac, and flowing N. for about 1,000 miles, during which course it receives the Umbamba, Tapichi, Mentaro, and other tributaries. it joins the Amazons in lat. 4° 40' S., long. 73° 80' W., and is navigable for large vessels as far as Sarayacu.