Recent years have experienced rapid urban growth in the Sharkia Governorate. These land demands contribute to a notable variance in Land Surface Temperature (LST), which aggravates the problem of Urban Heat Islands (UHI) caused by climate change. The purpose of this study is to evaluate and monitor LST and UHI changes in the Sharkia governorate and its districts using remotely sensed data from Landsat-8 with Operational Land Imager (OLI) in conjunction with Geographic Information System (GIS) techniques. Three Landsat-8 (OLI) images acquired in July 2002, 2012, and 2022 were calibrated and processed to map LST changes and identify UHI regions in the past 20 years. Results showed that throughout the whole study period. UHI showed a continuous increase to reach the maximum area in 2022 (128.14 km2). Urban Heat Islands of Sharkia governorate and its districts showed a continuous increase from 2002 to 2012 to 2022. However, New Salhia is the only district that had a decline in the UHI areas from 2002 to 2022 due to the land reclamation projects. The strongest UHI effect is seen in new cities, industrial zones, and metropolitan areas because of anthropogenic heat release. This is confirmed by the significant positive correlation between LST and NDBI (Urban Index). Thus, it was highly recommended that when developing and designing new cities, urban planners and architects should take into account metropolitan areas' thermal characteristics.