Moses Simpson Grist Mill (Site)

These coordinates mark the exact location where the mill once stood. There are no known photos of the mill. This photo is an example of how another Virginia grist mill was constructed in 1750.

In the mid to late 1700s to mid-1800s, Fairfax County was a sleepy rural farm area. Farmers grew grains for local consumption and exports, but like today, processed grain commands a higher price and is easier to transport. Since there was no electricity, electric motors or mechanical engines, local residents harnessed the power of water flow to power their mills. Their challenge was to find a site along a stream valley with water flow powerful enough to operate a mill, yet close enough to easily access. Fortunately, Fairfax County had an abundance of sites that allowed the milling industry to thrive.

Origin and Establishment (1773–1780s)

November 1773 Petition:
Moses Simpson petitioned the Fairfax County Court to build a water grist mill on Sandy Run, a tributary of the Occoquan River. The court appointed a jury of local freeholders (including John Hirst, William King, and others) to view the site and assess whether the mill would injure neighboring proprietors. Source: Fairfax County Court Minute Book 1772–1774, p. 326 (Library of Virginia microfilm).

Outcome:
The jury reported no material damage to upstream or downstream owners, and the court granted the writ of ad quod damnum in early 1774. Construction likely began shortly thereafter.

Acreage Condemned:
The standard allowance was 1 acre for the mill seat and abutments, plus the right to flood adjacent low grounds.

Physical Description and Location:
Sandy Run (then sometimes called “Sandy Branch”) flows through the modern-day Clifton/South Run area, near the intersection of Yates Ford Road and Henderson Road.

Mill Seat:
Likely near the confluence of Sandy Run and a smaller unnamed branch, where a 10–12 foot fall provided sufficient head for an overshot or breast wheel.

Archaeological Traces:
Stone foundation remnants were noted in a 1978 Fairfax County cultural resource survey (Site 44FX149). A mill race channel (approx. 300 ft long, 6–8 ft wide) is still visible on LiDAR imagery. Source: Fairfax County Park Authority files; Virginia Department of Historic Resources (DHR) Site File 44FX0149.

Ownership Timeline:
Moses Simpson from 1774 to 1798
William Simpson (son) from 1798 to 1825
John H. Ratcliffe from 1825 to 1837

Moses Simpson's son, William Simpson, inherited the mill and 120 adjoining acres. William Simpson was assessed tax on a grist mill in 1813 and 1815.

Operation and Economic Role:

Technology:
Likely a single pair of millstones (probably local sandstone or imported French burr), powered by an overshot wheel.

Output:
Typical for a small merchant mill: 10–15 barrels of flour per day when water was high.

Customers:
Served local planters within a 5-mile radius (e.g., Gunston Hall estate, Pohick Church parishioners).

Tolls:
Standard Virginia rate: 1/8th of grain ground (confirmed in 1785 Fairfax County Court order books).

War of 1812 Connection:

1813 Tax Assessment:
William Simpson paid $8.00 tax on “1 water grist mill” (valued at $800), indicating it was operational during the British blockade.

Strategic Value:
Sandy Run mills supplied flour to Alexandria merchants and possibly to U.S. troops at Fort Washington (across the Potomac). No direct requisition records survive, but proximity suggests likelihood.

Decline and Dismantling (1820s–1830s):

Competition:
Larger merchant mills on the Occoquan River (e.g., Chapman’s Mill, Yates Mill) drew away business.

1825 Sale:
John H. Ratcliffe purchased the property but converted the mill to a sawmill (1830 land tax notation: “saw mill formerly grist”).

By 1840:
The mill dam was breached, and the race filled in (per mutual deed of release, Deed Book C-3, p. 104).

Preservation Status:
The mill foundation is on private property within the South Run District Park buffer zone. Public access is restricted.