وَالْمَوَاقِيتُ الَّتِي لَا يَجُوزُ أَنْ يَتَجَاوَزَهَا الْإِنْسَانُ إِلَّا مُحْرِمًا خَمْسَةٌ
Translation: The boundary stations beyond which a person may not pass except in iḥrām are five.
These are the five appointed entry boundaries. A pilgrim travelling from outside them should enter iḥrām before passing the applicable station or its recognised alignment.
Muḥriman describes the legal state of iḥrām, not simply wearing two pieces of cloth. Remedies for improperly crossing a station are a separate detailed topic.