Sediments from an archaeological pit at the Tham Lod rock shelter in Mae Hong Son, Thailand, reveal sparse palaeoenvironment and palaeoclimate information in the northwestern region of Thailand and Southeast Asia. This study is a pioneering work for the site. Micromorphological, mineralogical, and geochemical methods were applied for analyses. The sediment profile was divided into two zones: the upper 0-338 cm depth and the lower 338-450 cm depth. Intense chemical weathering occurred in the lower zone, indicated by low quantities of kaolinite and high chemical index of alteration (CIA, 64.55-73.36%), reflecting greater humidity. The upper zone yielded mild CIA (47.21%) and contained ubiquitous smectite, indicating drier conditions. Overall sediments (along the profile, 0-450 cm depth) were affected by leaching and thin section analyses suggested a wet/dry cycle during diagenesis under humid tropical conditions. Micromorphological and geochemical analyses indicated that mudstone, sandstone, and limestone were major parent materials of sediments deposited mainly in a fluvial environment in the lower zone, which changed to a colluvial environment in the upper zone. The palaeoclimate during 12,770-33,340 yr BP was in the Last Glacial Maximum Period, characterized by drier and cooler than the present climate. The period 33,340 yr BP was wet and cool. Evidence of prehistoric human occupation, including bone and charcoal fragments, appeared in sediments in the upper zone, suggesting animal hunting for survival. Materials and Methods Micromorphological, mineralogical, and geochemical contexts are used in this work. Depositional sediments can record evidence or processes (Selley, 1985) that can be observed via micromorphology following the guidelines of Stoops et al. (2010). The aspect of geochemistry regarding the chemical processes of alteration, elemental signatures, and mineralogy, including clay-based minerals, can reveal the weathering intensity, sediment provenance, climatic environments, and anthropogenic input to the site. Study area The Tham Lod rock shelter site is located in the well-known archaeological pit in the Pang Mapha district in Mae Hong Son Province, Thailand. The shelter is located in a karst area at latitude 19°34′03′′ N and longitude 98°16′46′′ E, with an elevation of 640 m above mean sea level (Fig. 1). The pit is situated in a boundary of the Tham Lod Natural and Wildlife Education Center. The details of its physical characteristics have already been reported by Marwick (2013) and Chitkament et al. (2016).