The High Hay was a thick, tall hedge that bordered Buckland on the east.
High Hay protected the Hobbits of Buckland from the trees of the Old Forest which grew near it at many points. Planted many generations before the War of the Ring, they tended it carefully. The hedge was twenty miles long, starting at the Brandywine Bridge, looping away from the river, and ending at Haysend.
The Brandybuck Family had a private entrance through the High Hay to the Old Forest. A brick tunnel sloped down under the hedge and came out in a hollow on the other side. There was a gate of thick-set iron bars and a lock at the end in the Old Forest. This entrance is how Frodo Baggins, Sam Gamgee, Meriadoc Brandybuck, and Peregrin Took got into the Old Forest.
The trees of the Old Forest once attacked the High Hay, planting themselves beside it and leaning over it. The Hobbits fought back by cutting down hundreds of trees and making a bonfire. They burned the ground in a long strip east of the hedge. The ground stayed clear for about a hundred yards between the High Hay and the Old Forest.