The Greater Platte River Basin is an area that contains many fragile ecosystems that could be sensitive to changes in climate and land use. Geologic mapping of surficial deposits in the South Platte River in eastern Colorado and the Niobrara National Scenic River in northern Nebraska is underway to better understand the geologic framework of some of these ecosystems. The mapping, combined with geochronologic research, is key to understanding the timing and causes of landscape change in the two areas. National Aerial Photography Program (NAPP) color infrared photography, which can be viewed stereoscopically to enhance subtle topographic features, and NAIP digital orthoimagery are vital resources used in conjunction with field research to map surficial deposits in the two areas. National coverage and availability of the NAPP and NAIP imagery make these resources particularly useful to mapping throughout the conterminous United States. Lidar data recently obtained for the Niobrara National Scenic River further aid recognition and mapping of surficial deposits by providing crisp definition of subtle topographic features. Low fluvial scarps (less than 1 m high) between young river terraces can be resolved from the lidar data, and this high-resolution view of the landscape allows for a better understanding of recent river activity.