Big Spring Creek has played an important role in the agricultural and economic history of the Cumberland Valley. The five-mile-long creek emerges from an underground limestone spring about three miles south of this location, then flows northward through Newville before emptying into Conodoguinet Creek north of town. It is the fifth largest spring in Pennsylvania, with a median flow of 18 million gallons per day. With year-round flows of 50-degree water that do not freeze in winter, it became an ideal site for water-powered mills beginning in the 1760s, and two mills were established before the Revolutionary War. Historically, six mills operated on the creek, processing grain into flour, corn meal, and livestock feed for farmers between Chambersburg and Harrisburg. The Cumberland Valley Railroad in 1837 helped farmers ship mill products to distant markets. McFarland's Mill on the creek below this point operated as a grist mill from 1765 to 1827 and as a paper mill during the Civil War before being sold to the Newville Knitting Co. in 1898. Laughlin's Mill, the last remaining mill structure on the creek, stands in Newville one mile north. McCracken's Mill near the headwaters could produce up to 75 barrels of flour per day and generated about 35 horsepower, making it the most powerful mill in the area; owners Abram and John Manning supplied its flour to Queen Victoria in 1877, and the mill was later sold to state senator Samuel C. Wagner. Big Spring Creek is also renowned for recreation, especially fly-fishing, as one of the finest spring-fed native brook trout creeks in the United States, and in 2008 its upper section was estimated to contain more than 350 pounds of brook trout per acre.