Introduction: According to the flood records in Mazandaran province, this region is regarded as one of the flood-prone regions of the country, and due to the floods, it has suffered many casualties and financial losses. Therefore, this study aimed to investigate the settlements at risk of flooding as one of the main goals of this research. Methods: This descriptive-analytical study was conducted based on extensive and exploratory research approaches. The required data were collected from monthly discharge and the maximum instantaneous discharge in the stations of Mazandaran province along with the population statistics of the provincial cities, as well as the statistics of the Natural Resources and Watershed Management Organization concerning the floods. Accordingly, the statistics of hydrometric stations from 1971 to 2021 of Iran's water resources management main company, the population statistics of the province based on the census of 2015, and the statistics of floods that occurred from the beginning to 2021 have been used in this study. Flood return periods were obtained in the study stations in different statistical distributions using Hyfa software. Finally, Arc GIS software (version 10.3) was used to zone floods in Mazandaran province. Findings: Based on the results, about 1013 square kilometers of the province's surface accounting for 4.25% of its total area is located in the boundaries of large floods that have a return period of 50 to 100 years. Moreover, due to the high altitude, rainy-snowy events, and the significant amount of precipitation in Sarab (Dali Chai and Lar basins) and Payab, Haraz basin has a significant runoff rate discharge so that about 500 to 600 liters of water flow from this basin annually per square meter. Conclusion: According to the obtained results, strategies have been proposed to increase resilience against flood risk using different methods.
