Islam is a religion not a political country. Almost all countries of the world have Muslim citizens; either as majority or minority. However, around 50 countries in the world are having majority Muslim population.
Refer to related question below for more information.
Islamic front
Islamic countries are all over the world the Middle east, Africa, and the Far East, but are generally clustered around the Arabic states and around the religious homeland represented by Mecca in Saudi Arabia.
Middle east, India & Indonesia
in which parts of the world are there no islamic countries?
By forming Islamic armies, conquering non-Islamic countries, and making them into Islamic countries. Simple.
in which parts of the world are there no islamic countries?
If you mean, where Islam is not practised in toto, in letter and spirit, then most of the Islamic countries are not following Islam.
The most Islamic Countries are located in Europe,Asia and Africa.They are in this part of the World Because Islam started to spread from Saudi Arabia and slowly Islam expanded to Europe ,Africa Asia(etc)
The most populated Islamic countries in Asia are Indonesia, Pakistan, and Bangladesh.
I am not sure about the exact count, but many Islamic countries use the Arabic language.
The Persian Empire covered many countries, but was primarily based and organized in the modern state of Iran.
in mosque or Islamic centers or in Islamic countries like Iran