It was historically three districts: Mandera, Wajeer, and Garisa with Wajeer the biggest and Manera and Garisa same size. Today there are 4 with Garisa have been broken into Ijara (for the tiny hamlet of Masalani where Yusuf Haji finds his parliamentary seat) and Garisa.
There was a time when Beesha Sade ran over an entire 2/3 of the NFD, in Wajeer and Mandera. I think the Marehan on Snet have said many times they fought in British Jubbaland and when the ones left over in NFD refused to pay taxes, the British pushed all of them out. For example this is how Beled-Xaawo got started--the lady it was named after died recently I think. They were escaping the British pogram.
In the other topic about Jubbaland, I came across this quote
The United Nations Development Program magazine for Kenya on NFD information has this:Accompanied by 30 men from the Camel Corps and 30 mounted-infantry, he then proceeded towards Marehan country from Wajir to Elwak.
http://www.ke.undp.org/index.php/resources/download/34
Today Beesha Sade, after half a century after the pogroms, is making steps for comeback as we have witnessed the clashes Marehan nomads have engaged recently in Boru Hache, Mandera, and even back to Wajeer
