Three swamps, Daepyeong, Jilnal and Yujeon, distributed in Beobsu-myeon and Gunbug-myeon, Haman-gun, Gyeongsangnam-do, are investigated geomorphologically and geologically. The topography of the swamp area is low in general, though the northern side of Nam River has somewhat high mean altitude than the southern side of the river, consisting of lowly land, which is plane or peneplane. The swamps are only found in the southern side of the river, The swamp area is composed of greenish gray siltstone and fine sandstone of the Cretaceous Haman Formation, General strike of the rocks is N80°E, and dips 10°S. Crests of ridges of north-south trending hills are occupied with dyke rocks. The swamps are interpreted to be formed by migrated meadering course of Nam River, The meandering river migrated towards north leaving swamps. Gradually rising underground water-table was also the cause of swamp making. According to the size analysis of the swamp sediments, the mean size is 7φ sorting 2φ, and skewness +0.7φ∼-0.3φ Largest kurtosis is 1.20φ at the Yujeon swamp. The coarse swamp sediments is composed mostly of rock fragments of the Haman Formation, and fine-grained sediments consist of 50% quartz, 25% feldspar, 7% muscovite, 17% rock fragments and 1% biotite. Organic matter contents of the bottom sediments range from 2.53% to 9.82%, averaging 5.56% except two samples which have abnormally high contents of organic matter.