Pimmit Run is a stream that runs from the Pimmit Hills neighborhood in Falls Church and joins the Potomac River immediately south of Chain Bridge. The mouth of Pimmit Run provided Native Americans and settlers access to fresh water and fishing, the transportation of goods, and the opportunity to harness the water's power for industry. This location was the first break in the Potomac palisades (a line of steep cliffs) below Little Falls, which allowed for an early river crossing. Two Indian trails met at the mouth of Pimmit Run and archaeological evidence suggest that there was a Native American settlement here.
In 1719, Thomas Lee - former Virginia agent of the Northern Neck Propriety for Lady Catherine Fairfax of England - acquired a land grant near the current crossing of Chain Bridge and started developing the property. The Lee family established and operated a grist-mill and tobacco inspection warehouse that operated until 1792. While the tobacco warehouse was moved to Matildavile, near Great Falls, the industrial area at Pmmit Run expanded in the 1790s, when ownership passed to Philip Richard Fendall and Lewis Hipkins. By 1805, the new owners had improved the existing structures and constructed a merchant mill, distillery, brewery, granary, cooper's and blacksmith's shop, as well as cottages. Ownership of the property passed to Edgar Patterson, a Georgetown merchant who built a wool factory, cloth mill, and paper mill along the run.
During the War of 1812, a mill at Pimmit Run was used in the heroic effort to save the Declaration of Independence and other prominent government documents. On August 24, 1814, British troops marched on the District of Columbia, burning various portions of the district, including White House and Capitol. The day before the British attack, on orders from Secretary of State James Monroe, a State Department clerk named Stephen Pleasonton acted to secure the Declaration of Independence, the laws, the secret journals of the Continental Congress, and the correspondence of George Washington. According to Pleasonton, he proceeded to place the documents in linen bags and pack them in a cart for transportation to "a grist-mill, then unoccupied, belonging to Mr. Edgar Patterson, situated a short distance on the Virginia side of the Potomac, beyond the Chain Bridge, so called, two miles above Georgetown." On the morning of the attack, Pleasonton, fearing discovery of the papers due to the mill's proximity to Foxall's foundry, a military industrial center, moved the documents from the mill to Leesburg. The documents remained in Leesburg until it was safe to return them to Washington, D.C.
While various mills in the area may have remained operational until the Civil War, only a "Burnt Mill" is denoted on an 1864 map. In the 1890s, the Columbia Light and Power Company built a small hydropower plant near the mouth of Pimmit Run that suppplied electricity to the bridge and Canal Road. Between 1930 and 1950, the area underwent its last period of development as a tavern, two gas stations, and four cottages were located near Chain Bridge. All are no longer standing.