The Central District of Shahrud County () is in Semnan province, Iran. Its capital is the city of Shahrud.
The village of Ruyan was converted to a city as Rudiyan in 2016, and was renamed Ruyan again in 2021.
At the time of the 2006 census, the district's population was 142,663 in 39,805 households. The following census in 2011 counted 155,326 people in 45,464 households. The 2016 census measured the population of the rural district as 166,963 inhabitants in 52,694 households.