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Abundant sauropod, theropod and ornithopod dinosaur trackways and several footprint fossils occur in the Sagok Formation (Cretaceous) at Sinseong-ri, Cheongsong-gun, Korea. Based on Ortho Mosaic Image calibrated by UAV (Unmanned Aerial Vehicle), and 3D image map obtained by LiDAR (Light Detection and Ranging) and digital geometry, distribution of the trackways was identified. Occurrences of dinosaur tracks and sedimentary facies of the track-bearing deposits were described and the paleoenvironments were interpreted. The sauropod and ornithopod trackways represent their gregarious behavior. The theropod trackways show the characteristic of solitary behavior, whereas small theropod trackways discovered newly in this study show their gregarious behavior. The sedimentary facies of the track-bearing deposits are divided as follows: Interlaminated to thinly interbedded fine-grained sandstone to siltstone and mudstone; Bluish gray to light green calcareous sandy to silty mudstone; Light greenish gray muddy sandstone to sandy mudstone; Planar- to cross-laminated fine-grained sandstone to siltstone; Thin- to medium-bedded and graded medium- to fine-grained sandstone. They are interpreted as unconfined flow deposits formed on lake margin to shallow lake under paleoclimatic conditions with alternating wetting and drying intervals, and to have been intermittently influenced by pedogenesis. Mudcracks, wave ripples, small invertebrate trace fossils, weak pedogenesis and evaporite mineral casts are observed in the track-bearing deposits, suggesting that the paleoenvironments of the Sagok Formation at Sinseong-ri were lake margin (mudflat to sandflat) to shallow lake under seasonal climate in which arid climate prevailed and the lake was sometimes brackish during drying periods. It is interpreted that the Cretaceous lake and lake margin at Sinseong-ri provided a ecosite for diverse dinosaurs during arid condition.