Many grist mills existed in Fairfax County, Loudoun County, and Prince William County in the early 1800s to process farmers’ grain crops into flour. By this time, grains had replaced tobacco as the area’s main crop, in part because of the high prices farmers were garnering due to the increased demand for wheat and flour by Europeans as a result of the European War.

A study of the Mutual Assurance Society policies for mills in these counties was undertaken to determine if mill design was standard during that period. Insurance policies for sawmills and distilleries were also examined to determine how they were constructed, and if they were associated with grist mills. The policies provide a snapshot of what mills looked like at a particular period of time. The original date of construction for each individual mill was not provided; therefore, changes in style over time could not be evaluated.

The dates of the initial insurance policies range from 1796 to 1812, though most mills were first insured with the Mutual Assurance Society beginning in 1803. Forty-four grist mills were identified; thirty-three of which were in Loudoun County, five in Fairfax County, and six in Prince William County.

All but one of the mills were rectangular in shape. James Brown Jr. was the lone mill owner who had a square mill, measuring 28 feet each way. Several of the mills were unusually long. The 2-story stone mill at Coton owned by Thomas Ludwell Lee measured 34x98 feet, the 3-story stone mill in Occoquan owned by Nathaniel Ellicot & Co. measured 45x75 feet, and Elisha Janney’s 3-story brick mill in Occoquan on the north side of Water Street measured 44x68 feet. Three mills measured 40x50 feet.

The largest mill, with 10,125 square feet of space, was the Nathaniel Ellicot & Co. mill located in Occoquan on the Occoquan River. The smallest mill was a 2-story mill owned by James Nichols called Greenwood Mill. This wooden mill, with 864 square feet of space, had a stone foundation with an attached sawmill, which likely gave the mill its name.

The number of stories varied from one to four stories, though only one mill had but one story, and only two mills rose to four stories. Most of the mills (64%) were constructed with two stories. Three-story mills accounted for 23% of the mills studied.

Most of the grist mills (57%) were constructed completely of stone and another 25% were constructed out of stone for the first story and wood for the story(ies) above. It is interesting to note that out of the three mills constructed of brick, two of them were the 4-story mills. Only four mills were constructed completely out of wood, and they likely had stone foundations. Several policies mentioned that the lower level was partially underground, suggesting that the mills were constructed into a bank, similar to a bank barn.

Of the three brick mills, two were situated in Fairfax County and one in Prince William County at Occoquan. Therefore, it is possible that the large percentage of stone mills is influenced by the availability of that building material in Loudoun County.

The construction material for the roof of the mills, when it was mentioned, was always wood.

The insurance policies for 29 of the mills noted the number of pairs of millstones. In slightly more than half of these occurrences, the mills had two pairs of millstones. Another 34% had three pairs of millstones. In those cases where a mill had two pairs of millstones, one pair were burr millstones and one pair were country millstones. When a mill had three pairs of millstones, it utilized two pairs of burr millstones and one pair of country millstones.

The largest number of pairs of millstones any mill possessed was four pairs. William Hartshorne’s 4-story brick mill at Strawberry Hill in Fairfax County had four pairs of millstones. And, not surprisingly, so did Thomas Ludwell Lee’s 98-foot long mill at Coton.

Eight of the grist mills also had sawmills on the same property. There were no cases among the insurance policies where a sawmill was insured without there also being a merchant or country mill.

Each sawmill was a long, narrow structure. For example, Jonas Potts’ Waterford sawmill measured 13x42 feet, John A. Binns’ sawmill at Clover Hill measured 12x56 feet, and John Hamilton’s sawmill at Fornan Mills measured 12x56. None of the sawmills had the same dimensions as another sawmill. All were of wood construction, except John Chapman's mill in Prince William County that was constructed of stone for the first level and wood for the second level. When mentioned, each sawmill had a wood roof.

In addition to being long and narrow, the sawmills were typically only one story high. All five of the Loudoun County sawmills were one story high; however, both of the sawmills in Prince William County were two stories high.

Some of the sawmills were attached to the merchant or country mills, while others were near the mill. Jonas Potts’ sawmill at Waterford was only three feet from his mill, and John A. Binns’ sawmill was within six feet of his mill.

While many of the merchant and country mills were depicted with end chimneys, none of the sawmills had chimneys.

Three distillery buildings were insured: one at Woodlawn, one in Leesburg, and one at Thomas Ludwell Lee’s Coton. The distilleries were located at grist mills, except for the Leesburg distillery owned by Wilson C. Seldon, who possessed a mill elsewhere.

Each of the distillery buildings were one story high and covered with a wood roof; however, the similarities stopped there. Two of the distilleries were constructed of stone, and one of wood; and the dimensions of the buildings all varied.

While mills and sawmills had some similarities in construction material, general shape, and type of millstones used, the dimensions of the mills were not standardized in the early 1800s.

Sawmills and distilleries, at least in those few cases where they were insured by the Mutual Assurance Society, were associated with grist mills, and often located on the same property.