Miqat is the set boundary beyond which a Muslim intending to do hajj or umrah is not allowed to cross without ihram.
In essence there are two sets of boundaries. The outer boundary and the inner boundary. The first (marked red) highlights the point before which a person must start Ihram for those living beyond it. The second (marked blue) highlights the boundary of the haram and requires those living within to go beyond it and initiate ihram if they wish to do umrah such as the case of Hadrat Aysha (may Allah almighty be please with her) who whilst in Makkah was sent to Tan’im to put on her ihram for umrah.