Las Vegas - Approaching LAS from the east - what am I seeing? [was PHL to LAS]

I've been to Vegas now numerous times. However, everytime I fly from PHL to LAS I'm left wondering what I'm flying over druing the last hour or so. I know that it's mostly desert, but there is what appears from high up to be a river that runs for miles. It sort of looks like a bunch of canyons. Anyone know what it is that you fly over during this flight? Also anything else to look for on this flight as I will be leaving for LAS tomorrow?

the mighty Colorado River? I suppose if the approach is further north, it could be the Virgin River....

It's very likely Lake Mead, the Colorado River (Grand Canyon and side canyons), and Lake Powell.

It's a mix of the Colorado River and a little something called the Grand Canyon...

Much too narow to be the Grand Canyon I believe. Sounds like side canyons would make more sense. Thanks for the help.

Being in the plane does make things appear small :p
Hope I'll be able to get a window seat on my next trip to LAS (and during the daytime) so I get to see.

A few years ago, shortly after sunrise, the pilot announced the Grand Canyon was off the right side of the aircraft. I happened to be in the window seat.

Grand Canyon (http://farm3.static.flickr.com/2114/1510791239_fd699a0207_m.jpg)
Side Canyon (http://farm3.static.flickr.com/2171/1510791747_50144301a4_m.jpg)

Its most likely the Grand Canyon. The South Rim is the really pretty part. The Colorado river runs for "miles and miles" and it has done some might impressive work.

Grand Canyon National Park itself is huge, and is the adjoining Kalibab National Forest. Lots of pretty canyons and scenery.

http://en.wikipedia.org/wiki/Grand_Canyon

One useful trick... you can pull your flight's track into google earth via several flight tracking services... I think one of them (can't remember which) includes the prior days flights.

Shortly before arriving in las, you will pass near Hoover Dam and Lake Meade, depending on the route and the side of the plane you are on, there are two sides of the dam, the Lake Meade side (less impressive) than the full height 70 stories. At night it is lit up, making it even more impressive.