Seattle's topography, characterized by its hills and basins, has been shaped over millennia by geological processes, primarily glacial action. These glacial events have left a lasting imprint on the landscape, creating the elevations and depressions that define the city's geography. This natural molding has been a determining factor in shaping subsequent settlement patterns and urban development.

In addition to glacial influence, human activity has played a significant role in modifying Seattle's terrain. Throughout its history, the city has undergone extensive civil engineering works, such as hill leveling, filling of low-lying areas, and infrastructure construction, which have substantially altered the original geomorphology. These anthropogenic interventions have sought to optimize space for urbanization and transportation, superimposing themselves on pre-existing landforms and creating a hybrid landscape where natural and artificial elements intertwine.