This data set presents results from two groundwater tracing experiments conducted in the mudstone aquifer underlying the former Naval Air Warfare Center (NAWC), West Trenton, NJ. In each test, a bromide solution was introduced into a hydraulically isolated section of borehole 36BR (denoted as 36BR-A); the hydraulically isolated section of the borehole isolated specific bedding plane parting fractures intersecting the borehole 36BR. In the first test, initiated in July 2007, water samples were collected from borehole 15BR; borehole 15BR is outfitted with a submersible pump operating continuously as part of the pump-and-treat operation at the NAWC to prevent off-site migration of groundwater contaminants. In the second tracer test, initiated in September 2008, groundwater samples were collected from a hydraulically isolated section of borehole 73BR (denoted as 73BR-D2); a peristaltic pump was used extract groundwater from the selected interval. In each test, the groundwater samples were analyzed for the concentration of bromide using ion chromatography.