All territory east of the Colorado River is recognized as Caesar's land, an area indisputably under the control of the Legion and agents acting on Caesar's behalf.”— Fallout: New Vegas loading screen
The Colorado River is a main river in Nevada, Arizona, and Colorado. The Hoover Dam was built on this river. The Colorado River forms the dividing line between the New California Republic's offensive camps, and the Legion's forts. Neither side is willing to strike at the other over the river, forming the stalemate that Fallout: New Vegas is set around.
There is a path leading down to the river just north of the Abandoned BoS bunker. If you head north along the river towards the Hoover Dam, you will come across a cove on the east side with lakelurks and two explosives crates with some loot in them. If you head south on the west side just past the short narrow part (bottleneck) of the river you can find hidden in the weeds on the upper bank next to a skeleton, a half buried duffle bag of loot (a lakelurk may be nearby to the south). Further south on the east side of the river you will come across the deathclaw promontory. Farther to the south, directly across the river from Blue Paradise Vacation Rentals is a cove filled with lakelurks. In the cave behind the wrecked boat is a dead Mercenary and two duffle bags full of loot. All of this was found before the Courier gains access to the east bank of the river by Caesar's Legion. Pinto Beans can be found along the river banks.
- The water in the river is not irradiated at any point within the map. There is a point very far south outside of the map which is slightly irradiated. This is presumably due to Mr. House's defense system stopping any nukes that could've gotten radiation into the water.
- Joshua Graham states that Dead Horse Point is somewhere up the Colorado River from Zion Canyon.
- If a player heads east from Camp Searchlight to get there, after the rocky, downhill part leading into the sandier terrain, there is generally a pack of three to four fire geckos.
- When swimming through the water, one can see tires, boards and seaweed resting on the river bottom.
The Colorado River appears only in Fallout: New Vegas.