Au Gres' meaning and history: Au Gres means "of sandstone" because of the type of material on the river bottom. The City of Au Gres lies atop a glacial lake feature which consists of clay or shallow layers of sand over clay. In early years, Au Gres was considered a logging community; however, today the largest industry appears to be tourism. Both logging and tourism are probably a direct result of the Au Gres River which runs through the City and the availability of the City to Saginaw Bay and Lake Huron. The theme of this area used to be "Timber to Tourist" but now Au Gres is known as "The Perch Capital."