An e-Government portal is responsible to provide news, information and services to citizens, merchants and tourists in a reliable way. However, the rapid development of Information and Communication Technology (ICT) has given rise to an environment characterized demand and expectation for timely delivery of information and services and a requirement for ready access constantly, which changes rapidly according to the development of ICT. It is important to know if our e-Government Web portal always meets the demand. This thesis presents methods of measuring the performance and healthiness of an e-Government portal to ensure its efficiency and effectiveness. We propose an evaluation framework, which consists of a 24/7 monitoring system and a Web visualization system. We also represent websites as a forest of trees for comparative evaluation. Neither existing academic nor commercial products have ever been developed for assessing e-Government performance in this highly visual and interactive approach. Keywords: Web mining, Web visualization, Web graph, fuzzy association rule, monitoring system, e-Government evaluation.