At the time of the 2006 National Census, Mezerj's population was 3,704 in 873 households, when it was a village in Shirin Darreh Rural District. The following census in 2011 counted 3,766 people in 1,061 households. The 2016 census measured the population of the village as 3,834 people in 1,193 households, the most populous in its rural district.
123Jahangiri, Eshaq (25 July 2021) [مصوب (Approved) 3/5/1400 (Iranian Jalali calendar)]. تصويب نامه در خصوص تقسيمات كشوري در شهرستان قوچان استان خراسان رضوي[Letter of approval regarding national divisions in Quchan County, Razavi Khorasan province]. سامانه ملی قوانین و مقررات [National System of Laws and Regulations] (in Persian). وزارت کشور [Ministry of the Interior]. هیات وزیران [Council of Ministers]. پيشنهاد شماره [Proposal Number] 186259. Archived from the original on 5 May 2023. Retrieved 19 March 2026.
12سرشماري عمومي نفوس و مسكن 1395: استان خراسان رضوی[General Population and Housing Census 2016: Razavi Khorasan Province]. مرکز آمار ایران [Statistical Centre of Iran] (in Persian). Archived from the original(Excel) on 2 April 2022. Retrieved 19 December 2022.
↑Mousavi, Mir-Hossein (1 July 1987) [تاریخ تصویب (Approval date) 1366.4.10 (Iranian Jalali calendar)]. ایجاد و تشکیل 9 دهستان شامل روستاها، مزارع و مکانها در شهرستان قوچان تابع استان خراسان[Creation and establishment of nine rural districts including villages, farms and places in Quchan County under Khorasan province]. مرکز پژوهشهای مجلس شورای اسلامی ایران [Research Center of the Islamic Consultative Assembly of Iran] (in Persian). وزارت کشور [Ministry of the Interior]. هیات وزیران [Council of Ministers]. پیشنهاد شماره [Proposal No.] 11928.1.5.53. Archived from the original on 2 June 2014. Retrieved 3 February 2026.
↑سرشماري عمومي نفوس و مسكن 1385: استان خراسان رضوی[General Population and Housing Census 2006: Razavi Khorasan Province]. مرکز آمار ایران [Statistical Centre of Iran] (in Persian). Archived from the original(Excel) on 20 September 2011. Retrieved 25 September 2022.
↑سرشماري عمومي نفوس و مسكن 1390: استان خراسان رضوی[General Population and Housing Census 2011: Razavi Khorasan Province]. Iran Data Portal—Syracuse University (in Persian). مرکز آمار ایران [Statistical Centre of Iran]. Archived from the original(Excel) on 20 January 2023. Retrieved 19 December 2022.