Since the early colonial period, mills have operated on the rivers and creeks of Delaware, serving local farmers and residents. In the 1760s, a merchant flour mill was built on Red Clay Creek on the site of an early colonial mill. By the end of the century the mill had been upgraded with an automated milling system developed by Delawarean Oliver Evans. Operations expanded to include a sawmill, woodworking and wool processing in the 1800s, but business trouble and changing markets led to several changes in ownership.

In the 1920s to the 1960s, Greenbank Mill operated as a gristmill and was a center of activity in the community, the place to get flour, cornmeal, buckwheat flour, and animal feed. Local residents fondly remember miller Roy Magaragal - who learned his trade on the job and operated the mill until his death. Charles Biggers helped to deliver sacks of flour and feed to houses before he went into the service during World War II. He recalled the buzz of activity at Greenbank Mill

It was not just farmers who relied on the mill. Many families had their own pigs, chickens and other animals in their backyards that needed feed, and homemakers purchased flour to do their own baking. In 1969, a devastating fire gutted the gristmill and shut down operations after three centuries. Today, Greenbank Mill has been restored and operates as a historic site interpreting the technology of milling and telling the story of the mill's role in the community.