Open source technologies for geospatial data have dramatically expanded over the last decade. A new mapping application for the Gazetteer for Scotland (GfS) was created by following the Open Web Mapping approach, which describes how the combination of geospatial Open Standards and open source software (OSS) allows to create powerful and sophisticated map mashups. The study of the pros and cons of Open Web Mapping revealed the benefits of this approach for the GfS’s mapping application. The use of OpenLayers as the client-side technology proved to have several advantages which are discussed in this paper. The paper also focuses on the development of a modern and appropriate User Interface (UI) design for the GfS. User surveys and a critical evaluation of both the old and new map interface helped to develop a mapping application which combines important UI design principles and the implementation of new map layers and functionality. An analysis of the interests and browsing behaviours of the GfS users enabled the creation of a customised set of information and functionality. OpenLayers provided an excellent basis for the implementation of standardised data formats from different sources and a flexible way to implement the functionality needed to create the mapping application for the GfS.