Gamma rhythms (∼25–100 Hz) play a key role in cognition. Their disruption in neurological disorders such as Alzheimer’s disease (AD) has been linked to memory deficits and cognitive decline. Non-invasive audiovisual (AuVis) stimulation at 40 Hz (in the gamma range) has emerged as a promising intervention, as it reduces amyloid-β plaques, and improves behavioral performance of AD models in spatial memory tasks. Our previous work has shown that AuViS promotes synaptic plasticity, as seen by its positive effects on neurogenesis in the aging hippocampus. This suggests that cognitive improvements promoted by this treatment are likely supported by broad circuit-level modifications. To investigate the impact of AuViS on hippocampal network dynamics, we performed in vivo single-unit and local field potential (LFP) recordings across hippocampal subregions in 8-month-old mice exposed to chronic 40 Hz AuViS. We present a characterization of oscillatory power, cross-regional coherence, and ensemble activity during spatial navigation in familiar and novel environments before and after six weeks of daily stimulation. Our results provide mechanistic insights into the beneficial effects of AuVis stimulation on cognition in an aging brain.