At the time of the 2006 National Census, Sangdevin's population was 3,671 in 862 households, when it was a village in Katul Rural District. The following census in 2011 counted 4,119 people in 1,180 households. The 2016 census measured the population as 4,203 people in 1,255 households, by which time the village had been converted to a city.
12Rahimi, Mohammad Reza (19 June 2013) [تاریخ تصویب (Approval date) 1392/03/29 (Iranian Jalali calendar)]. تصویب نامه درخصوص تبدیل روستای سنگدوین از توابع دهستان کتول بخش مرکزی شهرستان علی آباد در استان گلستان، به شهر[Approval letter regarding the transformation of Sangdevin village from the functions of Katul Rural District, Central District of Aliabad County in Golestan province, into a city]. لام تا کام [Lam ta Kam] (in Persian). وزارت کشور [Ministry of the Interior]. هیات وزیران [Council of Ministers]. شماره ابلاغیه ۱۰۳۳۱۴/ت۴۹۰۰۷هـ [Notification number 103314/T49007 AH]. Archived from the original on 25 June 2025. Retrieved 5 December 2025.
12سرشماري عمومي نفوس و مسكن 1395: استان گلستان[General Population and Housing Census 2016: Golestan Province]. مرکز آمار ایران [Statistical Centre of Iran] (in Persian). Archived from the original(Excel) on 29 March 2019. Retrieved 19 December 2022.
↑Jahangiri, Eshaq (4 January 2020) [۱۳۹۸/۱۰/۱۴ (1398/10/14) (Iranian Jalali calendar)]. تصویبنامه در خصوص تغییر نام شهرستان علیآباد استان گلستان به علیآباد کتول[Approval regarding changing the name of Aliabad County, Golestan province, to Aliabad-e Katul]. پژوهشکده حقوقی شهر دانش [Shahr Danesh Law Research Institute] (in Persian). وزارت کشور [Ministry of the Interior]. هیات وزیران [Council of Ministers]. پیشنهاد شماره ۱۳۳۴۲۸ [Proposal No. 133428]. Archived from the original on 24 March 2023. Retrieved 5 December 2025.
↑سرشماري عمومي نفوس و مسكن 1385: استان گلستان[General Population and Housing Census 2006: Golestan 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 گلستان[General Population and Housing Census 2011: Golestan Province]. Iran Data Portal—Syracuse University (in Persian). مرکز آمار ایران [Statistical Centre of Iran]. Archived from the original(Excel) on 17 January 2023. Retrieved 19 December 2022.