This study was conducted to evaluate the distribution of magnesium fractions and their relationship with soil properties in ten representative calcareous soils from the Duhok governorate, Iraqi-Kurdistan region, including Baedra, Sulav, Rashank, Sarsing, Qadish, Heteet, Darhozan, Mahet, Girguran, and Zawita. Soil samples were air-dried, ground, and sieved to 2 mm to assess physical and chemical properties as well as magnesium forms, including organic, acid-soluble, exchangeable, mineral, and total magnesium. The studied soils exhibited slightly alkaline pH, calcareous characteristics, and textures ranging from clay to sandy clay loam, with non-saline conditions. Organic magnesium constituted a small portion of total magnesium (approximately 6-9%), showing a strong positive correlation with organic matter and moderate correlations with potassium and itself. Acid-soluble magnesium represented 35-52% of total magnesium and was positively correlated with organic matter and exchangeable magnesium. Exchangeable magnesium accounted for roughly 11-21% of total magnesium and correlated strongly with soil pH and active calcium carbonate content. Mineral magnesium comprised 21-56% of total magnesium and correlated significantly with exchangeable magnesium. Total magnesium showed significant positive relationships with organic matter, exchangeable magnesium, and acid-soluble magnesium, highlighting the interconnectedness of these fractions in calcareous soils. These findings indicate that exchangeable and acid-soluble magnesium are the most influential fractions, emphasizing the importance of managing soil organic matter and carbonate levels to optimize magnesium availability. This, in turn, has implications for soil fertility, crop nutrition, and sustainable management practices in calcareous soils of the Duhok. By focusing on essential findings and their practical relevance, this study provides a clear overview of magnesium fraction dynamics, offering guidance for improved soil management and agricultural productivity.