McConnell Springs are the visible portion of an underground drainage system that underlies part of central and south Lexington. When limestone bedrock is near the surface, rain and melted snow pass through the soil into the limestone, finding horizontal and vertical cracks in the rock, gradually enlarging them over thousands of years. The resulting landscape, usually characterized by sinkholes, springs and caves, is called karst topography. The sinks and rises of McConnell Springs form windows along the flow path of underground streams, where the subterranean conduits are briefly exposed before vanishing again into the rock.
The second spring of the McConnell Springs system is called the Boils because of the action of the water emerging from the underground conduit. During heavy rains a column of water rises from the spring to a height of up to 24 inches. This spring and the Blue Hole are both considered “artesian” springs.