The river segment in Colorado had originally been named the Grand River because its origins in Rocky Mountain National Park (as a tiny stream draining a wet meadow) fed Grand Lake and then went through Granby. Some water was collected in the Never Summer Mountains on the western slope and diverted into the 14 mile Grand River Ditch, a water diversion project which flowed over the Continental Divide at LaPoudre Pass (elevation 10,175 feet) and delivered water for eastern plains farmers. Here's a photo of the narrow, tranquil, and shallow Colorado River at its headwaters in the Never Summer Ranch...
The Grand River also influenced the naming of several down-river locales besides Grand Lake and Granby. Miles later, the river flows through "The Canyon of the Grand River" which is now named Glenwood Canyon. One of my favorite bike trails runs through the canyon, alongside the river as part of the I-70 highway...
...and provides amazing close-up views of the rafters and white-water kayakers on the river...
In the photo below (which was taken from the bike trail) I'm sitting in the front-left of a raft as we battle a rapid in the Colorado River...
Next comes the town of Grand Valley which has since been renamed Parachute, Colorado. And finally, as you near the border with Utah you reach Grand Junction, so named because the Gunnison River joins the once-named Grand River at this point. The town has an amazing riverside bike trail that runs for 28 miles, connecting several river towns.
Here's another map showing the drainages into the Colorado River...
In 2007 I did a double adventure in Colorado's Royal Gorge. I'd been high above at the bridge several times but never at the bottom, so I first rode the train through the canyon and then whitewater rafted it. No photos of my raft, but here's a shot I took from the train...
Moab, Utah is on the Colorado River adjacent to Arches and Canyonlands National Parks. The river is a bit tamer here but still gives a nice whitewater rafting experience. I'm in the front obscured by the water in this 2008 photo...
Below is a shot of one of my two 120 mile canoe trips down the Green River from Green River, UT to the Confluence with the Colorado River in Canyonlands National Park, at which point a jet boat from Moab picked us up and returned us up-river to Moab because canoes cannot negotiate Cataract Canyon's rapids below the Confluence (which by the way was so named by John Wesley Powell in 1869 when he made his first trip here.)
At the end of both canoe trips, as we camped at the Confluence waiting for the jet boat, how I longed to make that right turn onto the Colorado River and continue down through the turbulent Cataract Canyon, but of course couldn't. Finally, a few years later I did! The Sierra Club offered a service project removing invasive tamarisk trees at the Confluence. By necessity, we had to raft to the Confluence from Moab, do our work, and then exit through Cataract Canyon's rapids. What a great raft trip that was! Here are info and photos of Cataract Canyon and the service project.
Below is a photo I took of the Colorado River from our hike high up to the mesa as we camped along the river...
...and here's a photo as we entered Lake Powell at the end of Cataract Canyon, beneath the Highway 95 bridge (also called the Hite Crossing Bridge)...
After Cataract Canyon, the Colorado River enters Lake Powell National Recreation Area, created by the Glen Canyon Dam at Page, Arizona. Below are two aerial shots of magnificent Lake Powell and a few of its side canyons, several of which we explored by houseboat and kayak on my two houseboat adventures there (in 2003 on the western end, and in 2012 one on the eastern end of the 186 mile-long long lake.)
Kayaking the side canyons is a wonderful way to explore Lake Powell...
Fifteen miles after Lake Powell (below Glen Canyon Dam) you arrive at Lee's Ferry, the put-in for raft trips through Marble Canyon and then the Grand Canyon. I was fortunate to raft the entire Grand Canyon in 1999 and here are a few photos and comments.
Finally, in 2002, I kayaked 50+ miles from the base of Hoover Dam (Lake Mead Recreation Area) through the Black Canyon/Lake Mohave portion of the Colorado River. Here are some photos and info from that 5 day kayaking/camping Elderhostel program.