Soil organic carbon (SOC) is a crucial component of the soil carbon pool, and its content directly reflects soil fertility. Investigating the spatial distribution of SOC and its influencing factors in Ordos City can provide scientific support for regional carbon neutrality and sustainable ecosystem development. Based on measured soil data and the CatBoost machine-learning model, this study estimated the spatial distribution of SOC at different soil depths in Ordos City and identified the main influencing factors. The results showed that the average SOC contents in the 0-10, 10-20, 20-30, and 30-50 cm soil layers were 10.26, 8.36, 7.05, and 4.83 g/kg, respectively. Spatially, SOC content was higher in the east and lower in the west. SOC content and its spatial heterogeneity gradually decreased with increasing soil depth. Soil physicochemical properties, such as pH and electrical conductivity, played important roles in SOC accumulation and distribution.