Is it his house, his street, his suburb, the Metropolitan Phone Code area, Local Council or County Limits? There are no signs for City limits as each Country has their own definition of City, ie. It could be the Central Business District, or it could be the greater suburban area too depending on the context of speech.
Answer
If a person intends to undertake a journey of 48 shari miles or more, he will
be a musafir and will have to make qasr (perform 2 rakats in Zuhr, Asr ,
Esha salaats) after leaving the housing area of his town. However, the
calculation of 48 miles will commence from the time of making the intention,
if it is from ones house, then from there.
And Allah Ta’ala knows best
Mufti E. Desai