I just landed in Houston, mainly to see the eclipse next week. Originally I was going to view from Austin, but it's because of this that I decided to trek to Dallas instead.

Essentially "totality" is inside the moons shadow. Since the moon is spherical (well, mostly), the shadow it casts is a circle. That's the path of totality.

I know you know this, I'm just saying this because you see that black band and you think all totality is the same. It's not. If you're on the edges, imagine a big circle shadow. Easier to visualize this way.