Search for dry camp site with google maps White green area ?

Best thing to do is in the upper left corner you'll see Search Nearby: Hotels Restaurants. Click there and in the search box enter Campgrounds and hit enter. The campgrounds will highlight on the map. If you double click on one it will bring up info and link to a website for the campground. Zoom out the map to see more area and campgrounds.

Otherwise look on the Bureau of Land Management website for Colorado