For some whose frame of reference for the word "labyrinth" would be a muppet musical starring David Bowie, a couple of quick notes:
What we're concerned with here is the open-air path style of labyrinth, an excellent example of which can be experienced at the Sacred Oak Grove, an alternative-spirituality retreat in Sorgho, KY, Daviess County. The Labyrinth of Sacred Oak Grove is based on the one in the Cathedral of Notre Dame in Chartres, France, built in 1201.
Sacred Oak Grove's mission statement is "to create, improvise and nuture a sacred transformational environment, in order to remember, validate and illuminate our divine connection". It's the project of Clarice O'Bryan, who describes herself on her website as "teacher, healer, dancer, intuitive masseuse".
There's also a smaller, but very interesting, open-path labyrinth at Hopscotch House, a women's retreat off Wolf Pen Branch in Prospect.