[5] At the time of the 2006 National Census, the city's population was 7,273 in 1,860 households, when it was in the former Mehdishahr District of Semnan County.

[citation needed] Shahmirzad has been home to people of diverse ethnic backgrounds, a large group of whom seasonally settled in cities and towns of Mazandaran, such as Babol, Sari, Neka, and Behshahr.

During the past decades many Muslim, Bahá'í, and Shahmirzadi Jews,[8] migrated to larger cities in Iran and abroad, most notably San Francisco Bay Area.

Shahmirzad's walnut orchard with a size of 700 ha is noted by the UN, Food and Agriculture Organization, as the largest of its kind in the world.

[9] Shahmirzadi homeowners are given a proprietary interest in the walnut orchard in proportion to the amount of land they own in the village.