As the geographical information changes continuously, it has been difficult to manage it in consistent manner. Especially different terminologies are often used for describing the same object. These characteristics of geographical information make the information search be very unproductive. Recently, it is widely recognized that capturing more knowledge is the next step to overcome the current difficulties on sharing geographical information. In this paper, we utilize the ontology concept in order to facilitate information search for geographical data in the internet environment. A prototype of search system implemented using the ontology for river-related data is presented.