Update: 4610-foot explored cavern under McIntyre Spring.
Blue Spring between Quitman and Valdosta has been known since the settling of Brooks County, when it was used as a reference point in building roads starting in 1859. Here’s an early 20th century report, with a much later picture postcard (probably not the same building) and location map.
A Preliminary Report on the Underground Waters of Georgia, by S. W. McCallie, State Geologist, Geological Survey of Georgia, Bulletin No. 15, 1908, digitized by Google, Page 58, Brooks County,
With the exception of the town of Quitman, the entire domestic water-supply of Brooks county is practically obtained from the shallow wells, which penetrate the Lafayette sandy clays, or the underlying Miocene beds. There are a few large springs in the county; but they are always located in more or less inaccessible places; and, as a result, they are only occasionally used for domestic, or other purposes. There is, however, in the case of the so-called Blue or Wade Mineral-spring, a rather marked exception to this general rule. This spring, which is located near the right bank of the Withlacoochee River, seven miles east of Quitman, has, in recent years, become quite a local pleasure resort. The improvements con- sist of a small hotel, or boarding-house, and a number of cottages. for the accommodation of guests. The spring is a typical so-called blue spring, of the limestone region of South Georgia. It seems to be the outlet of a large subterranean stream, which ascends, with considerable force, through a large opening. At the time of the writer’s visit to the spring, in November, 1903, a rough estimate showed, that it was then flowing about 15 million gallons per day. It was learned, however, that, during an extremely dry season, some years ago, the spring went dry. Another of these large springs, known as the McIntyre Spring, having probably twice the capacity of the Blue Spring, is to be seen in Withlacoochee River, near the Georgia-Florida line, 15 miles southeast of Quitman.
There was a historical populated place called McIntyre Spring in that location, now no longer visible, at 30.641039 -83.3665392, according to GA HomeTownLocator, presumably drawing on Census Bureau data. The surrounding land has road frontage only on Rocky Ford Road, and is owned by William Luther Sullivan of Madison, Florida.
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