This question has caused great division and long debates within the Muslim community, I will try to shed some light on the issue and hopefully make it clear what the correct position is.
Firstly, all we know about Allah is that he is a thing, that exists, and everything about Him is different to us.
The question about Allah’s whereabouts assumes that He is the same as other things. It would be like me saying, my car has a weight, therefore my anger must have weight as well, “How many kg does my anger weigh?” The concepts are not interchangeable. The question itself assumes knowledge and limitation about Allah, which is false.
This is from Al Kafi:
H 215, Ch. 2, h 1
Muhammad ibn Ya‘qub has narrated from Ali ibn Ibrahim, from Muhammad ibn ‘isa from
‘Abd al-Rahman ibn abu Najran who said the following.
“I asked Imam abu ‘Abdallah about the Oneness of Allah saying, ‘Can I think of Him (the
creator) as a thing?’” The Imam replied, “Yes, but not as something well understood and
clearly defined with in limits. What may become a subject of your thoughts is different from
Him. Nothing resembles Him and the thoughts and imaginations can not reach Him. He is
different from what can become the subject of thoughts and is different from whatever that
can be perceived in ones thoughts. You can think of Him as some thing but not well
understood and clearly defined (under certain limits).”