It is believed the mill was built by Willoughby Newton between 1753 and 1759. The mill was owned and operated by Edward Caple by 1850; and on a military Civil War Map, it is noted as "Copels Mill". Names 150 years ago were not always written down, sometimes just spoken, hence many misspellings.

Through its history, it ground various grains and then sumac for local tanning and dying. The last owner/operator, Henry Nichols, ran the mill as a grist & saw mill through 1916. The saw mill being functional after 1906.

All mill operations ceased by 1929; when, Rocky Run was diverted, the headrace filled, and other renovations completed by various non-milling owners. The water wheel, mounted on the east end of the structure-left side of the mill in this photo- and all machinery were stripped away in the 1940s

The mill, vacant for about half a decade, was purchased c. 1935 by Ellanor Lawrence and her husband David, the founder of the US News & World Report magazine, as part of the Washington estate they made their home.

The Lawrences transformed the mill into a guest house for many of Washington's notables. It was also the site of Mr. Lawrence's weekly NBC Network news broadcasts, aired from 1945 through 1970.

Upon the passing of Mrs. Lawrence, the mill, miller's house, and surrounding woodlands were donated to the Fairfax County Park Authority in 1971 as a memorial to Mrs. Lawrence.

The Fairfax County Park Authority has renovated the exterior and interior to serve as a public park facility. The mill was known variously as Newton's Mill; Caple's Mill; Rocky Run Mill; Triplett's Mill; Pittman's Mill; Sandy's Folly; Middlegate; and lastly, Cabell's Mill today.