Likely one of the most frequently visited Ozark springs, due to picturesque setting. Alley holds the record for the largest credible measured flow of any Ozark spring ( 2750 cfs or 1.776 billion gallons of water, on April 22, 1974.) According to Josiah Bridge, an early geologist, Alley is known to have stopped flowing for 12 hours sometime in the 1920's, as a result of a massive collapse known as "The Drop-In" near Summersville. It resumed flow, albeit in a muddy condition which continued for several days as the water removed the debris from its conduit.
Brief History: Delaware Indians removed to the area used the spring, until it quit flowing temporarily, coincident with the New Madrid earthquakes of 1811-12. Spring was settled in 1848 by James Tackett, and officially homesteaded ten years later by James McCormack. The first mill was built in 1870 at Barksdale Spring, as it was known until John Alley relocated to the hamlet, bringing the post office name of Alley with him. In 1893, George McCaskill built the present mill with a steel turbine as power source. Around the turn of the century, the mill changed hands four times. The fifth time, Conrad Hug, of the Chrystall Springs Townsite Co. from Kansas City, bought spring, mill, town, and all, intending to establish a resort and "townsite" for city dwellers. The mill closed in 1918. With the surrounding area badly logged off, and railroads leaving the area, Hug and company sold 407 acres, including spring and mill to the new state park system. Alley Spring State Park opened in 1925. It, along with Big and Round Spring State Parks, were transferred to federal ownership in 1971.