Maps for Climbers

CalTopo
Rockd makes geologic info accessible. It's good for information about the rock-type of a particular crag, or for discovering rocks exposures. There are also apps available.
The Bureau of Land Managment has some of the more permissive Recreation Opportunities
Forest Service
From the The USGS
The National Map and it's intro page
For custom, printable topographic maps topoBuilder is quick, easy, and free.
HeyWhatsThat is a fun explorer for checking horizon visibility.
AcreValue offers land-ownership maps. Outside of your local government offices, it's one of the better ways to find out who owns land that rocks are on.
Bing Maps has better rural satellite resolution than other big map providers. In some regions, it offers oblique imagery, available as "birds eye"; this is about as good as it gets for boulder hunting on satellite images.
Vexcel Imaging and EagleView are paid services but if you can get access, their imagery is about as good as you can get.
OpenStreetMap
Free Campsites is what it sounds like and little more.

building maps