The one who passes the miqaat and forgets to enter ihram has to go back to his miqaat
Praise be to Allaah.
If this man was one of the people of Riyadh and he went to as-Sayl and entered ihram from there, he does not have to do anything because he entered ihram from his miqaat. But if he came from Madinah, he should have gone to the miqaat of the people of Madinah and entered ihram from there, and if he entered ihram from as-Sayl, then he has to offer a ransom (fidyah), because when the Prophet (blessings and peace of Allah be upon him) defined the miqaats, he said: “They are for them and for anyone who comes to them who is not of their people.” Passing the miqaat of the people of Madinah, for one who passes by it who is not one of them, is like the people of Najd passing the miqaat of the people of Najd when they did not enter ihram. End quote.