The Humboldt River is a body of water in Liberty City which separates Algonquin Island from Broker, Dukes and Bohan, with Charge Island and Colony Island located on the river. It is named after the fictional explorer Horatio Humboldt.
The river is implied by the documentary "A History of Liberty City" to be heavily polluted before even the establishment of the city itself, due to the natives using it effectively as a sewer.
- Its real life counterpart is the real life Hudson River, as the main and bigger river in New York. Its location is based on the East River. It is not influenced by the real Humboldt River that runs through northern Nevada.
- The game makes many references to murderers and serial killers hiding the bodies of people they have killed, or want to kill, in this certain river.
- Niko Bellic executes Vladimir Glebov and disposes of his body in the Humboldt river during the mission Uncle Vlad.
- Patrick McReary talks about dumping victims into the Humboldt in Undertaker, with Derrick or Francis' body.
- Johnny Klebitz says the same thing in the mission Roman's Holiday, stating "I've seen some of the bodies you guys drop in the Humboldt" to the Russians.
- Because of the first meeting with Eddie Low, he may also use the Humboldt River to hide corpses.
- In Grand Theft Auto: Chinatown Wars, the protagonist, Huang Lee, is left for dead at the bottom of the river.
- A Tug Boat can be found under the Algonquin Bridge.
- The real Humboldt River runs through northern Nevada in the western United States.