I tried to find the graft union but I cannot find the diagonal line. I think this is a sucker but I didn't just want to chop it off just in case it wasn't.

thorns indicate a seedling which is what the rootstock is. remove it

Citrus produce very fast-growing, vertical, large-leafed branches called "gourmands", or frequently 'water-sprouts' that use a lot of water and nutrients, take a long time to produce with generally poorer quality fruit, and frequently lots of thorns. These should be removed where they grow out of the trunk. Yours looks like a gourmand. Whether it's a gourmand or a rootstock sucker, definitely remove it.

Y'all gave me awesome information. I really appreciate it! Branch removed!!

FYI . That is Tri-folate (root stock). You can tell from the three part leaf. It is not water sprout, which would have the same leaf structure as the remainder of the plant (and Tangelos are not three leaflet).

Definitely good that you cut it. The citrus forum is the better place to post since it's a home to a bunch of citrus obsessed owners!

Ahhh okay. Thanks for the tip!