On the east side of the Shell River as it flows through the community of Shell Rock is the Shell Rock Grain and Milling Company building (1858). The two-and-a-half-story mill building sits on a high rock foundation looking directly over the river. The upper story, quite typical of mill buildings, has a high central monitor that runs from one end wall to the other. Wooden pegs rather than nails or bolts were utilized in much of the original structure (there are a number of later additions). In recent years the mill has used electricity rather than water power. The mill is situated beside the river just off route C45 and Iowa 3.