A deposit or photo ID is required. Like all Smithsonian facilities, the Zoo welcomes service animals. However, such animals must be walked to another area of the park in the unlikely event that Zoo animals become disturbed. The Zoo occupies a hillside rising 180 feet above Rock Creek. More than three miles of paths slope downhill from the Connecticut Avenue entrance.
Some paths are quite steep and can be slippery when wet.
Steep-grade symbols mark difficult parts of the pathways. Olmsted Walk, the main path, goes past all the animal houses except the Bird House and the Amazonia Science Gallery. The walk ranges from gently sloping to steep. The Valley Trail goes through the steepest part of the Zoo. People with mobility limitations should be especially cautious.