Tucked away in a Woodland hollow on a path in Orinda's Tilden Park is a bit of a post office, which looks like it was built by a fairy bureaucrat, and which regularly receives letters from hikers and children looking to have a twee exchange with the creatures of the forest.

Installed in December 2013 in a tree at the Curran Trail Park Fork, the small post office was not expected to last long. The original office consisted of a miniature mailbox in front of a pint-sized office complete with desk, lamp, a thimble-sized birdcage, and tasteful art on the wall. It looked, for all intents and purposes, as if a studious squirrel had set up a shop in the tree.

The creators of the post office have left a few letters in the mailbox, and after a few months, they have simply left the whole thing to exist in secret. Much to their delight, when they returned to the spot six months later , they found that, instead of deteriorating under the weather and the woods, the post office seemed to be expanding.  Wanderers who had stumbled upon the post office had added decorations, such as miniature wall maps and trinkets on the desk; new notes had even been written and left in the mailbox.

Soon the creators regularly checked the mail and had whimsical exchanges with unknown recipients who wrote letters to fairies and field mice. To this day, the tiny post office still sits in the tree, often distributing bite-sized newspapers ('The Small Times') alongside small letters. The office continues to grow and change, occasionally being rearranged or redecorated, but always giving a sense of wonder to all those lucky enough to find this postal knot.

Lea Redmond of Berkeley's Leafcutter Designs built "The Tiny Tilden Post Office" in a tree on the Curran Path in Tilden Park. The little treehouse was a thank you to the writer and editor Gareth Branwyn, who wrote down the Rabbit Hole, an article about Redmond, for Boing Boing. He called Redmond "to do the work of a fairy."

"She writes tiny little letters on a tiny stationary and seals them with wax inside a small, stamped, canceled envelope," Branwyn wrote about Redmond 's business. "The letter is then placed by the official World's Smallest Postal Service Employee (er ... Lea) inside a tiny blue post box."