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This map locates surficial geologic deposits of Quaternary age in the greater Denver area and surrounding region. Physical properties of the deposits are described. The physical properties include dominant grain size, composition, potential to expand upon sorption of water, and others. Origins and ages of the deposits, and their inherent geologic hazards are identified. The properties of deposits and materials on and near the land surface affect its suitability for societal uses. Examples of such use include large-scale landfill sites, gravel pits and rock quarries, large-scale residential developments, greenbelts, utility lines, and roads. Planners, zoning officials, builders, and interested citizens should have a clear grasp of how the properties of surficial deposits affect the growing urban sector within the Denver 1 ° × 2 ° quadrangle. This map provides basic data that can be used to derive other maps that show suitability of land for specific purposes. Apart from its usefulness to urban planning, the map can be a tool for the management and research of natural resources. It can enhance ecological surveys that were made by using satellite imagery. Certain biogeographical habitats, for example foothill woodlands and alpine forests, are influenced by soil-related factors and correlate well with certain units on this map. Other map data such as the ages and origins of the Quaternary surficial deposits are essential to any geomorphologic study of the Denver quadrangle. MAP UNIT NAMES The map unit names derive from a classification of geologic surficial materials. The names are based on prevalent grain size, minerals (or rock types), and geologic origin. Examples are “bouldery crystalline-rock landslide deposit ” and “stabilized dune sand.” Large areas (generally>1 km2;>0.4 mi2) of exposed bedrock, mostly devoid of surficial materials, are mapped with a symbol “R.