This according to wikipedia and http://esa.un.org/unpp/
I find this a bit strange since I’ve always learned that those countries counted borders to the Mediterranean
There are numerous ways to categorize countries.
One definition of North Africa that is currently popular is to identify those countries in which the Muslim expansion had a direct and lasting impact on their development. (This gives us the abbreviation M.E.N.A. for Middle East/North Africa to identify the current struggles with Islamist Islam.) Under this definition, Sudan is very clearly part of North Africa.
Another method of categorizing African regions places a (not quite artificial) line through the sahel, the agricultural region just south of the Sahara. In this method, Africa is divided between North Africa and Sub-Sahara Africa. Since Sudan is on the Saharan edge of the sahel, it would fall into the North Africa region.
Another method would be the one with which you are familiar, making only Mediterranean-coast countries part of North Africa. Under that scenario, Sudan would not be included, but you would need to identify your audience and your definition before you used the term.
Which part? Northern Sudan is largely Arab and Muslim, making it best classified with North Africa. The southern part is largely black and animist, like “sub-Saharan Africa”. The division is at the source of its long civil war.
UN geographic groupings - footnote A is pertinent.
thanks
and Egypt is part of both North Africa and Middle-East
(I label them first and foremost as a part of the Middle East and not NA)
The Middle East is however a political definition and not a geographical one (since it actually lies in “West East”)
You’re lucky Collounsbury is banned, or he’d go off on you for that. Northern Sudan is just as black as southern Sudan. It’s Arab only linguistically.
You were saying?
Read your own cite:
The Arabs are black. They call themselves Arabs because they speak Arabic.
I’ve never said there’s no such thing as a dark-skinned Arab. The north-Sudanese ones are, however, culturally quite distinct from the population of southern Sudan - which was the point, after all.
And because they are, in fact, Arabs.
So what color *do * Arabs have to be to qualify as such? 
Ar·ab Pronunciation (rb)
n.
- A member of a Semitic people inhabiting Arabia, whose language and Islamic religion spread widely throughout the Middle East and northern Africa from the seventh century.
- A member of an Arabic-speaking people.
I submit that one cannot be black and meet the conditions in (1), which is the sense in which I had thought you were using ‘Arab’ in your first post. It is, after all the primary meaning of the word. I apologize if you were not. Given the question asked by the OP, the distinction between the two meanings is worth commenting on.
I said “Arab” to describe the main population of the northern part of Sudan.
If you really want to explore this backwater of discussion, here’s a long list of different definitions to chew on, none of which describe the black animist/Christian people of sub-Saharan Sudan.
“The Sudan” refers to a large chunk of North Africa just south of the Sahara, not just the nation of Sudan (just like “America” refers to a good chunk of the Western hemisphere, not just the US). It’s basically the dividing line between “North” and “Sub-Saharan.”
Since the nation of Sudan is bordered by Egypt on its north and shares a Red Sea frontier with the Arabian peninsula, I have very little trouble considering it “North African.” Africa is friggin’ huge and Sudan is well into its northern half.
Oh come now, Elvis. You said northern Sudanese were Arabs, and southern Sudanese were black Africans. That was the contrast you drew. ‘Black Africans’ is neither a linguistic or cultural classification, but a racial classification, and given the grammar you used it was natural to take your use of ‘Arab’ in the same sense. I have no objection to your using the term ‘Arab’ to describe northern Sudanese, but for you to say “Northern Sudan is Arab while southern Sudan is black African” seems pretty silly since northern Sudan is also black African.
Really, just drop it. Just pretend that your post was unintentionally unclear and I pointed out a clarificatory note, and just let it all go.
Arabness has no relation to skin color. It’s a matter mainly of speaking Arabic as one’s native language. Or, as Ali Mazrui explained the long-term gradual Arabization of Sudan in The Africans, having one’s father identified as Arab is what counts in that patrilineal system.
For a real puzzler, try to figure out what Somalia is doing in the League of Arab States… (hint: it has nothing to do with ethnicity and everything to do with tribal genealogy, which is done similarly in both cultures.)