Do the regions in Soul Eater match perfectly to the real world?
Yes, it is related to the real world. There's no map ever shown, but Death City is a fictional city set in Nevada, USA.


  Shibusen is an academy located in the fictional Death City, of Nevada where Meisters and Weapons attend.


Source: Soul Eater wiki: Shibusen

Also, it's not listed, but I'm quite sure (judging by appearance) that Deng Dinga is from Africa, and Djinn Galland is from Western Asia.