The Petoskey, Michigan library is home of the Petoskey Commuity Labyrinth:
The meandering but purposeful path of the labyrinth is a metaphor for life. Unlike a maze, there is only one path in and out. There are no shortcuts, no dead ends, and the entire path must be followed to complete the journey. The labyrinth visually reminds us that we are walking a common path. Often circular in design, they represent wholeness and unity. Interest in the labyrinth as a tool for relaxation, healing, building community, solving problems, and nurturing intuition, creativity, and artistic expression has increased significantly over the past several years. They can be found in hospitals, parks, schools, prisons, retreat centers, faith- based organizations, and private gardens.
I was also able to find a library labyrinth in Estacada, Oregon; I'm sure there are others somewhere on some big list or that comments here can help make that big list.
The most notable fictional library as labyrinth would be Borges "Library of Babel", published in the US in the collection Labyrinths. Here's a certain Christopher Rollason on Borges’ “Library of Babel” and the Internet:
Borges wrote “La Biblioteca de Babel” in 1941, and it was published the same year in the collection of stories entitled El jardín de senderos que bifurcan (The Garden of Forking Paths)11. The infinite library is presented from the viewpoint of one of its denizens, “los hombres de la Biblioteca” (“the men of the Library”), who was born in the library, has spent his life among the bookstacks, and knows he will die within its walls. This, certainly, could be read as prefiguring the inhabitants of today’s or tomorrow’s world of virtual information, with their consciousness saturated by an endless flow of cyberdata. The volumes of Borges’ library add up in their totality to the sum of all texts ever written, and, indeed, all texts which could possibly ever be written – and, going well beyond that, also contain every possible combination of letters in every language and, at least by extension, every script: “la Biblioteca es total y ... sus anaqueles registan todas las posibles combinaciones de los veinticuatro símbolos ortográficos ... en todos los idiomas” (“the Library is total and ... its shelves register all the possible combinations of the twenty-odd [the Spanish text says “twenty-four”] orthographical symbols ... in all languages”).
Nice to have then a real (and finite) labyrinth with one path to contemplate the world with, when you are faced with an infinite collection of all symbols in all languages.
(We'll be near Petoskey on our way up north this summer; thanks to Michael Stephens for the suggestion.)