Depends on how you calculate it, check the Cencus site for more info, look for District of Columbia in the charts. Per household it's about 47,000
They are called the Atlas mountains and run mostly through Morocco in north west Africa and consist of the moyenne atlas ( medium ) and the haut atlas (high)
The Appalachian Mountains are found in North Carolina Virginia ,Virginia,Maine,New Hampshire,Vermont,New York,Massachuetts,Conneticut,Pennsylvania,Ohio,West Virginia,Kentucky,Tennessee,Alabama,South Carolina,Georgia,Indiana,Illinos,Missouri and Arkansas