Came here to ask this. What the heck! Here it is: https://imgur.com/a/vXwqO

EDIT: Never mind, apparently it's oil and gas refineries! https://www.reddit.com/r/answers/comments/4x0v1e/why_is_ther...

This map must be a little out of date - North Dakota is now an explosion of light from natural gas venting in its oil fields:

https://worldview.earthdata.nasa.gov/?p=geographic&l=Referen...

That's where the oil is as well as relatively cheap electricity. The area is quite developed for the purpose of extraction.

And the coast of Nigeria has some odd lights as well.

edit: and in the middle of their national forest o_O

This is Ural - https://en.m.wikipedia.org/wiki/Ural_(region)

Metal heart of Russia. Industrial core of country.

I was surprised by that too. It's huge. First I thought it's the Moscow area.