Question Summary:
What is the distance one should keep from a non-mahram?

Question Detail:

How much distance should a woman keep from marriageable males? I mean like at what distance it is considered ‘mixing’? and what does it really mean to ‘mix’ with men? Ive heard that to mix with marriageable men is haram. please explain this concept.

Answer :

In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
Shari’ah has prohibited intermingling with the opposite gender to avoid immoral contact and relationship between each other. Therefore, whatever distance will lead to immoral contact will be prohibited. The distance could be through direct contact, for example being in close proximity or even indirect contact through means of communication, telephone, email, text, etc.  
Consider the following Hadith:
عَنْ حَمْزَةَ بْنِ أَبِي أُسَيْدٍ الْأَنْصَارِيِّ، عَنْ أَبِيهِ، أَنَّهُ سَمِعَ رَسُولَ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ، يَقُولُ: وَهُوَ خَارِجٌ مِنَ الْمَسْجِدِ فَاخْتَلَطَ الرِّجَالُ مَعَ النِّسَاءِ فِي الطَّرِيقِ، فَقَالَ رَسُولُ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ لِلنِّسَاءِ: «اسْتَأْخِرْنَ، فَإِنَّهُ لَيْسَ لَكُنَّ أَنْ تَحْقُقْنَ الطَّرِيقَ عَلَيْكُنَّ بِحَافَّاتِ الطَّرِيقِ» 
Narrated AbuUsayd al-Ansari: AbuUsayd heard the Messenger of Allah (ﷺ) say when he was coming out of the mosque, and men and women were mingled in the road: Draw back O women, for you must not walk in the middle of the road; keep to the sides of the road.[1] 
 
It is further mentioned:
عَنِ ابْنِ عُمَرَ: «أَنَّ النَّبِيَّ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ، نَهَى أَنْ يَمْشِيَ يَعْنِي الرَّجُلَ بَيْنَ الْمَرْأَتَيْنِ»
Narrated Abdullah ibn Umar: The Prophet (ﷺ) prohibited that one, i.e. man, should walk between two women.[2]
It is clear from the above mentioned Ahādith that no man or woman (i.e. ghair-mahram) should come close to each another unnecessarily. They should avoid crossing paths with one other and abstain from attending the same gathering as men if there are no facilities of hijāb (barrier) and hijāb is not practiced. [3]
And Allah Ta’āla Knows Best
AbdulMannan Nizami
Student Darul Iftaa
Chicago, IL, USA
Checked and Approved by,
Mufti Ebrahim Desai.
www.daruliftaa.net