One of the largest terrain corrected synthetic aperture radar (SAR) mosaics, a mosaic of the state of Alaska, was created from 800 ERS-1 SAR summer images. Because of rain events, significant temporal changes of soil moisture often cause substantial changes in the signature of adjacent SAR images acquired on different dates. After an extensive search for suitable images from a large database of the available 1992 and 1993 images, a nearly seamless large-scale digital mosaic of Alaska was successfully generated at a pixel resolution of 100 m. The applications potential of the mosaic are demonstrated by examples in mapping soil moisture, forest fire scars, glaciers, geological, and volcanic features.