Ontario’s Oak Ridges Moraine has been the focus of attention for many decades now. Stretching some 160 km across south-central Ontario, the moraine consists of permeable stratified sediments and serves as the drainage divide separating waters flowing south into Lake Ontario from those flowing north into Lake Simcoe and eventually into Georgian Bay. Often referred to as Ontario’s rain barrel, the moraine is an important hydrogeological feature serving as the primary recharge area for over 30 watersheds. For 25 years now, a partnership of local government agencies has been working to synthesize the hydrogeological understanding of the moraine and its surroundings, and, through an interactive mapping web portal, to provide access to the data and analyses that support this understanding. What has resulted, is a unique groundwater management program with an overall drive to improve land use and water related decisions. Through the Groundwater Project, the Oak Ridges Moraine Groundwater Program (ORMGP) has prepared a soon to be released ebook; the focus of this presentation. The book summarizes the current hydrogeological understanding of the moraine as well as touching on the unique elements of the management of some $1 billion in accumulated and interpreted digital hydrogeological infrastructure.