This section of the guide will list down the locations and their notable loots or items of interest. The game doesn't really restrict you from visiting these locations unless they're part of a story so live the Fallout experience by exploring them at your own pace.
Discovering a new location will give you a bit of EXP and allows you to use it as a fast-travel point. There are some instances where new locations are marked in your map like NPC conversations, reading notes, listening to holotapes, reading terminal logs, or quests. When a previously unknown location is marked on the map, you won't be able to fast-travel there unless you head to the actual location on foot.
Also, some areas have particularly high level enemies such as behemoths and deathclaws. You don't necessarily need to engage them but if you feel that you can't safely explore the area, try exploring the common areas particularly near the center of the Commonwealth until you get stronger and have better equipment.

The game has a lot of unmarked locations for you to explore. These locations usually have loot so don't hesitate to take a detour and explore them. Sometimes, you'll also encounter random events or random NPCs. These usually doesn't have any important effects to your quests but they make the wasteland a lot more livelier so to speak.

This section of the guide will be updated as we play through the game. If we missed anything and if you want to add, please don't hesitate to comment on the location's page so we can update it and give you due credit. Thanks!
