Worldwide, soil organic matter (SOM) levels have been on the decline, resulting in a general decline in soil health, particularly in agricultural areas. Changing agricultural management and climate have been related to this change in SOM, but detailed information regarding the relationship is scarce. The objective of this research is to assess and quantify changes in SOM content within the agricultural regions of Southern Ontario, using Middlesex County as a representative area. Digital soil mapping is used along with legacy and recent field-collected soil data to assess how SOM levels are changing with time. Results showed that SOM levels were on a decline, with changing climate correlating the most to this change, followed by crop type and management. This study could benefit decision-makers and producers by enhancing the understanding of the impact of agricultural decisions on overall soil health and help build future policies.