A hollow is a small valley or depression in the landscape, typically found nestled between hills or ridges. These natural bowls in the terrain often collect water and sediment, creating sheltered environments with their own distinct microclimate. In forested areas, hollows tend to be cooler and more humid than surrounding slopes, supporting lush vegetation and serving as natural corridors for wildlife movement.

Hollows form through various geological processes, including erosion, where water gradually carves out low-lying areas, or through the settling of land over time. In hiking contexts, you'll often encounter hollows in mountainous or hilly regions where they provide natural routes through otherwise steep terrain. These features can range from barely noticeable dips in the ground to substantial valleys spanning several acres.

Hikers should be aware that hollows may retain moisture longer than surrounding areas, potentially creating muddy conditions or seasonal streams, and can occasionally present navigation challenges due to limited sight lines and dense vegetation. The sheltered nature of hollows also means they can be excellent spots for wildlife observation, particularly during dawn and dusk hours.