This four story, 50' square, brick and stone mill was built in 1838 by William Cooch Jr. to replace a nearby earlier mill. The top story was not considered a floor for tax purposes with its Mansard/French Second Empire roof.

Levi Cooch's heirs controlled the mill in 1870, a year later, tranferring ownership to William Cooch & J. Wilkins.

The mill was retrofitted to operate using the new roller process of flour production in 1884. Steam was used when water flow was low, utilizing a boiler and engine. The roller mill produced 75 barrels of flour a day, requiring the labors of four men and a headrace of three-quarters of a mile above the mill.

Dayett Mills (onounced Die-ett) is the third mill built by the Coochs in the local area. In 1894, it passed from the family ownership with its sale to John W. Dayett.

Dayett's widow sold the mill to Jonathan Irwin and in 1948, the William Johnsons and Charles Goth bought the mill.

Fires in 1916 and again in 1933 caused relatively minor damage; though not enough to preclude rebuilding, resulting in the mansard roof the last rebuild.

The earlier mill replaced by the current mill, was built c. 1700. William James, the builder, suffered the loss of his grist mill & saw mill in 1707; his mills were seized and sold at public auction. Howell James purchased the mills and 200 acres, willing them to his son, Phillip,in 1717.

In 1737, Phillip sold the mills to John Jones of Philadelphia in 1737. Joseph Brown found himself the owner four days later. Brown continued to operate the mills until 1746, when Thomas Cooch held title to same. The British burned the 1700's grist & saw mills during the revolution in 1776. In 1791, the property came into the control of Thomas's grandson, William Cooch, who built a new mill the following year in 1792. He managed the mill until his death in 1838, when William Jr. built the third andd current mill.

The yield of flour increased with the roller process and by-products of the bran and middling were used in the manufacturing of livestock feeds. The mill came under the jurisdiction of the State of Delaware, with control administered through the Division of Historical and Cultural Affairs. The mill was the second last mill in the state of Delaware to still be operating when it closed in 1996.