Systems and methods are disclosed for providing portable device presence utilizing environmental ambient audio fingerprints. Portable devices provide media exposure data and environmental ambient fingerprints to a processing device, where the environmental ambient signatures provide at least one characteristic of the ambient audio surrounding each portable device. The environmental ambient signatures are then processed to determine if they match. Portable devices associated with matching signatures are identified. Ambient fingerprints may also be used to establish a logical location where media exposure took place. The ambient signatures are alternately combined with monitored data to provide more robust data sets for contextual processing.