Penladen Hills constituted a region located on the planet of Naboo, accessible by traveling up the Solleu River from Theed, the primary city. During the Invasion of Naboo in 32 BBY, the Penladen detention camp was situated there.
Ultimately, Jason Fry, the author of The Essential Guide to Warfare, decided to remove all references to Penladen Hills from the finished work. Subsequently, the hills achieved canonical status through the StarWars.com blog post titled Star Wars: The Essential Guide to Warfare: Author's Cut, Part 6 — Showdown at Naboo.