In the early days, flour mills were located on streams where water power was available. One of the earliest mills in Washington County was Lehman's Mill, located north of Hagerstown on Marsh Run, a tributary of the Antietam Creek, only one half mile from the Pennsylvania line.

The mill, known then as Marsh Mills, reportedly was built in 1760 by Thomas Spriggs, who owned a 1,500 acre tract called Spriggs' Paradise on which the mill was situated. Spriggs' original mill was a two-story stone structure. Power for the mill was derived from a half-mile long dam, which was thought to have been dug by slave labor.

In 1854, Jacob Lehman purchased the mill and 10 5/8 acres along Marsh Run just east of Reid along what today is Lehman's Mill Road. In 1869, it was replaced by a brick building by Henry Lehman, who had purchased it from his father Jacob's estate. In 1887, steam power operated the mill, which is thought to be the oldest operating mill in the East.

For more than 100 years, the mill was owned and operated by four generations of the Lehman family, producing barrels of flour, rye and corn chop. Henry's son, William Barton(1855-1940), passed the operation of the mill to his son, also named William Barton. In 1969, the mill finally passed from the Lehman family when William Barton sold it to Better Foods Foundation, Inc.