Stanza 1 Summary

Get out the microscope, because we’re going through this poem line-by-line.

By a route obscure and lonely,

The poem opens on a mysterious "route," a path or a road from one place to another. We don't know where we've come from or where we are going. We only learn a few things about this path.
First, it's "obscure." That means dark and dim, but also hard to find, remote, or distant. "Obscure" is a great Poe word, full of the spooky mystery that's everywhere in this poem.
He also tells us that the road is "lonely." That sense of being alone and abandoned is another big theme in this poem (and in a lot of Poe's work).
In just a few words, without telling us much of anything specific, Poe has set the mood for the entire poem.

Haunted by ill angels only,

We seem to have crossed over into some kind of spirit world, and not a happy one.
The road is apparently haunted by beings that the speaker calls "ill angels." "Ill" could mean either evil or sick, but the important thing to check out here is the contradiction in that phrase.
We usually think of angels as being happy and bright, but there's clearly something wrong with these dark, unhealthy, bad angels. Poe surprises us, forces us to shift our perspective, and pulls us deeper into his world.

Where an Eidolon, named NIGHT,

This is probably the first line you'll trip over, mostly because of that crazy word "Eidolon." Poe does that on purpose. He loves to use big, fancy words, partly because he loves how they sound, and partly because they startle readers a little, and force us to sit up and pay attention.
Never fear, though, Shmoop won't leave you in the dark! An eidolon is a phantom, just the kind of spooky, ghost-like figure you'd see in a dream.
The fact that the phantom's name is "NIGHT" just drives home how dark and scary he is.

On a black throne reigns upright,

Apparently NIGHT "reigns" (rules) like a king, from a black throne.
Notice that last word, "upright." He's sitting up rigid and straight on his throne.
We're definitely supposed to be scared by this dark ghost sitting on a black throne. We can't help but think of Sauron in The Lord of the Rings.

I have reached these lands but newly
From an ultimate dim Thule—

Now we get a little more info about the speaker of the poem. Apparently he just got to this new place. He's coming from somewhere called "Thule."
That needs a little background. In ancient literature, Thule (that's pronounced THOO-LEE) was the name for an island at the end of the world, the farthest place you could go. "Ultima Thule" was even farther out, a way of referring to a place outside the known world. So when Poe talks about "ultimate dim Thule," that's a fancy way of saying some dark place beyond the edge of the world.

From a wild clime that lieth, sublime,
Out of SPACE— out of TIME.

This line describes what that "ultimate dim Thule" is like, although it doesn't clear things up much.
Poe gets pretty fancy with the vocab here, so we'll break it down: our speaker is arriving from a "wild clime" (that just means region, place, area) that "lieth" (yup, that means lies, or is located) sublime (stunning, awe-inspiring, terrifying) outside of space and time. In plain English, he's telling us that he's coming from an amazing place that's beyond space and time. Much clearer now, huh?
Remember that a lot of Poe's work is about creating a mood or feeling in the reader, not just giving you information. This whole first stanza is a description of a trip from one place to another, but more importantly, it's trying to make you feel the power and the mystery of Poe's imagination. That's why those big, rich, weird words are in there.