Geoportals (geographic portals) are entry points on the Web, where various geographic information resources can be easily discovered. They organize geospatial data and services through catalogs containing metadata records, which can be queried in order to give access to related resources. However, the current organization of geographic information in metadata catalogs is unable to capture the semantics of the data being described; therefore users often miss geographical resources of interest when searching for geospatial data in the World Wide Web. In this paper, we present an innovative approach in the development of geoportals, based on the next generation of the Web, called the Semantic Web. This approach relies in the organization of the geo-data at the semantic level through appropriate geographic ontologies, and the exploitation of this organization through the user interface of the geoportal. To the best of our knowledge, this approach is the first that combines the expressiveness of geo-ontologies in the context of geographic portals.