This study focused in developing a web-based GIS COVID-19 thematic map to support the LGU of Magalang, Pampanga in their COVID-19 cases monitoring activities using QGIS and other tools. Specifically, it aimed to describe the relationship of age and sex of COVID-19 patients in municipality of Magalang in terms of: total, active, recovered, and death cases; to distinguish the reason/s of transmission of the COVID-19 among the patients in the municipality of Magalang; and to analyze the trend and identify which barangay/s in the municipality is/are most affected by COVID-19. The researcher gathered data and information about the confirmed COVID-19 cases in Magalang, Pampanga from the Rural Health Unit of the municipality. The researcher also gathered data from every barangay of the municipality for the population data needed in the study. The Geographic Information System (GIS) was used to produce GIS-based thematic maps for monitoring and analyzing COVID-19 cases in the municipality. The study was made possible with the use of several software applications, namely Microsoft Excel Wordsheet, Quantum Geographic Information Systems, Qgis2web Plugins, HTML, Infinity Free and Sublime Text. The research concluded that the age group that was mostly infected by COVID-19 in the municipality was the 20 to 29 years old bracket with 228 (23.29% + 0.31%) total cases recorded. Additionally, in comparison to female patients with COVID-19, male patients had a considerably higher risk of death. Patients above the age of 40 years old had a much higher risk of death than those under the said age. Based on the result, the main reason why the COVID-19 patients in Magalang got infected by the virus was by having close contact to the person with the disease (51.96.