This is the Colorado River where it becomes Lake Mojave, the larger bulge in the upper center of the image. The river is the state boundary between Arizona on the left and Nevada on the right. The Colorado River flows south into Lake Mojave and over the horizon as it winds its way south towards Mexico. In this image taken at dusk you can see the alpenglow light cutting across the canyon floor from right (west) to left (east). Shadows of the Eldorado Mountains are darkening the ground on the top left of the image, becoming more pronounced and longer as time rapidly closes the window on another beautiful day.
On the right lower side of the image is Opal Mountain and at its base along the bend in the river is Nevada Bay and Opal Cove. Directly across the river is Elephant Hill and above that along the river is Mount Davis and Jeff Davis Cove. These lands are harsh and difficult but stark as they may be, they provide a wonderful tapestry of color and texture and are beautiful reminders of the diversity of shapes, colors and creativity of our wondrous planet. It is lovely the way the shadows reveal details of the terrain in the lower part of the image.