Intense and frequent climate extremes are causing unprecedented impacts on human and natural systems. For instance, extreme heat events are resulting in enormous stress on infrastructure such as the electric grid, human health impacts, and fueling wildfires. The impacts associated with climate extremes will likely continue to worsen with the projected increase in their severity in a warming climate. The extent and severity of these impacts make it crucial to understand their characteristics in historical and future climate. Earth system modeling tools are generally used to understand the characteristics of these climate extremes at global, national, and regional scales. This presentation will focus on the use of General Climate Models (GCMs), regional climate downscaling and data analysis tools to evaluate climate extremes in historical and future periods over the conterminous United States. Specifically, the focus will be on the development of high-resolution climate projections based on the latest suite of sixth Phase of Coupled Models Intercomparison Project (CMIP6) GCMs that can be subsequently used to understand the climate extremes and associated regional scale impacts.