Beginning at 3rd level, you can use your action and expend one ranger spell slot to focus your awareness on the region around you. For 1 minute per level of the spell slot you expend, you can sense whether the following types of creatures are present within 1 mile of you (or within up to 6 miles if you are in your favored terra in): aberrations, celestials, dragons, elementals, fey, fiends, and undead. This feature doesn't reveal the creatures' location or number.
Primeval Awareness
Ranger Feature