The Laramie River is a tributary of the North Platte River, approximately 216 mi (348 km) long, in the U.S. states of Colorado and Wyoming. It rises in northern Colorado, in the Roosevelt National Forest in the Front Range, in western Larimer County. It flows NNW into Wyoming, along the east side of the Medicine Bow Mountains, past Jelm and Woods Landing, then NE emerging from the mountains near Laramie. North of Laramie, it flows north through the Laramie Plains and through Wheatland Reservoir. It flows NE through the Laramie Mountains. Emerging from the mountains, it receives the North Laramie River 5 mi (8 km) north of Wheatland and Chugwater Creek 7 mi (11 km) NE of Wheatland. It joins the North Platte opposite the town Fort Laramie. In its upper reachest in Colorado, the river supplies water to the Cache La Poudre River via the Laramie-Poudre Tunnel. The tunnel, which is approximately 2 mi/3.2 km long, was finished in 1911 as part of a larger irrigation project for northern Colorado.
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The river was named for Jacques La Ramee, a French-Canadian fur trader who lived in the area in the 1820s. His arrow-ridden body was found near the mouth of the river on the North Platte by his companions, who named the river in his honor. The Laramie Mountains, as well as the City of Laramie, Wyoming, were later given the same name.
