Greenhorn Grove is a large, forested area that can be found in the Frontier. This large, forested area is notably known to border Topple Hill and The Deep Forest. It's known to be filled with a variety of trees that provides shade for the creatures on the ground. This place is abundant to a variety of mushrooms, like Flatty Mushroom and Lumoore Mushroom. Some players will visit this area to mine the ores that can be found in Greenhorn Grove as it's close to Topple Town. This place is inhabited with monsters on some days and Deers may make an appearance in the forested area.
Greenhorn Grove also has a cave, however, it requires the player to travel to The Quiet Field to find the cave entrance. When entered, this place has a few spots for miners to mine ores and it's usually inhabited with Glow Mushrooms. Other than that, there's not much in it.
The Interdimensional Traveler can also appear in Greenhorn Grove. Collectus can be found here as well, however, it's required for the player to enter the "Death Portal" at Rubble Spring. From there, the player will be on the top of the grass pillar and they may interact with the NPC if they want to.