The first settlers of the Pacasmayo valley, or the ones whose existence is known were the cupisnique, with an antiquity of approximately 11000 B.C. to 3500 B.C. The mochica culture also had a presence in the valley, between 500 B.C. and 800 B.C. During the 900 AD, the chimu culture appears, leaving to the future the famous archaeological center of Pakatnamu. The inca culture also came to Pacasmayo, just little time before the Spanish arrival, although they did not have a great influence on the historic legacy of the region. Its foundation as city took place during the colonial period in 1775. It's believed that the origin of the word Pacasmayo comes from the quechua Pakatnamu, the name of the founder of the fortress that keeps the same name. Othe theories support that Pacasmayo means hidden river.