Venture into some of the most breathtaking vistas, but do so equipped with a fine topo map.
This series of National Geographic's Trails Illustrated Arizona Rock Mountain Maps lets you select one of two maps: the Grand Canyon Bright Angel Canyon N/S Rims (covering the highest-visitation areas of the park surrounding the South Rim visitor center and the Bright Angel Trail), or a broader East/West Grand Canyon Map (including the outer reaches of the canyon). In addition to trails, campgrounds, river crossings, and points of interest, these waterproof and tear-resistant maps provide info on wilderness travel, safety, and local flora and fauna. Includes UTM grids for use with your GPS unit.
I've used it once or twice and have initial impressions
High quality topo map with many trails and features listed for the Grand Canyon. I've only used the N/S rim version of this map. But, seeing as this is the most popular region of the park, it will most likely cover the areas you need. If you're a hardcore explorer or canyoneer, you'll want the east/west version, too.