Spending the nights of the 11th, 12th (and optionally 13th) in মিনা is ওয়াজিব; being present for the majority of each night fulfills the requirement, and missing it without excuse requires fidyah.
Yes, staying overnight in মিনা during the Days of Tashreeq is considered wajib (ওয়াজিব) by the majority of scholars. Specifically, হাজীগণ should spend the nights of the 11th and 12th of Dhul Hijjah in মিনা, with the 13th night being optional (as early departure on the 12th is permitted). The requirement is to be present in মিনা for the majority of the night — roughly from Maghrib (sunset) to Fajr (dawn).
The tent cities of মিনা are organized by country and হজ্জ group, with assigned camps. Life in the মিনা tents is communal and simple — হাজীগণ sleep in air-conditioned tents, share meals, and use their time between stoning rituals for worship, কুরআন recitation, and rest. The days in মিনা are spiritually significant as they are the Days of Tashreeq, during which নবী করীম (সাল্লাল্লাহু আলাইহি ওয়া সাল্লাম) said: 'The Days of Tashreeq are days of eating, drinking, and remembrance of Allah.'
If a হাজী does not stay overnight in মিনা without a valid excuse, a fidyah (sacrifice of a sheep) is required জমহুর উলামাদের মতে. Valid excuses include: genuine inability to find space in মিনা (which does occur due to overcrowding), medical emergencies, or being assigned accommodation outside মিনা boundaries by the authorities. Those whose camps are technically outside মিনা's boundaries should still spend as much time as possible within the boundaries.
নবী করীম (সাল্লাল্লাহু আলাইহি ওয়া সাল্লাম) said: 'The Days of Tashreeq are days of eating, drinking, and remembrance of Allah Most High.'
নবী করীম (সাল্লাল্লাহু আলাইহি ওয়া সাল্লাম) said: 'The Days of Tashreeq are days of eating, drinking, and remembrance of Allah Most High.'
Source: Ibn Qudamah, Al-Mughni; al-Nawawi, Al-Majmu
নবী করীম (সাল্লাল্লাহু আলাইহি ওয়া সাল্লাম) said: 'The Days of Tashreeq are days of eating, drinking, and remembrance of Allah Most High.'
Sahih Muslim #1141 (sahih)