A 40'X 50' 2.5 story stone/stucco, frame structure built by Jacob Keller or Jacob Keller Jr. in 1814. Some historians feel Jacob Keller had an earlier mill in 1783-88, and that Samuel Keller had this early mill from 1789 thru 1714. Jacob Keller Jr. had the new mill thru 1826. Another Keller desendant owned thru 1880, when John Stoll bought out Keller. Stoll kept it for about 10 years and sold to John Rettew (Rettew Mill-name).

The Guy Bard/Keller's Mill Covered Bridgewas built in 1891 as a 77' single span Burr arch truss. The mill had a 1300' headrace, falling 6'in height from the dam, with a 300' tailrace back to the Cocalico Creek. The flour, grist and cornmeal mill utilized 2 turbines to produce 25 bbls. of flour a day.

The mill burned but was built again with only 2.5 stories. Vacant mid 1960's thru the late 1980's. By 1994, the condition was critical as the deterioration was approaching ruins status, with the roof gone.