While there are some rules governing the use of "the" with proper nouns, no rule alone will always be of help when deciding whether to use "the" with a particular noun. The best way to learn is to commit to memory all those nouns that take "the" and those that don't. For example, you will say "Mount Everest" but "the Matterhorn".
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.