The compound-specific hydrogen isotopic composition (delta H-2) of n-alkanes is a valuable proxy to investigate hydrological conditions in lake sediments. While terrestrial n-alkanes reflect the isotopic signal of the local precipitation, aquatic n-alkanes incorporate the isotopic signal of the lake's water, which can be strongly modulated by evaporative enrichment. So far, the spatial distribution of the terrestrial and aquatic delta H-2 signal within lakes have not systematically been investigated. Here, we present compound-specific delta H-2 results of terrestrial (delta H-2(C31)) and aquatic (delta H-2(C23)) n-alkanes of surface sediment samples from Lake Khar Nuur, a semi-arid and high-altitude lake in the Mongolian Altai, and additionally investigate the delta H-2 signal of topsoils from the catchment. Our results show that the majority of the n-alkane delta H-2 values from the catchment topsoils correspond well with modeled local growing season precipitation (JJAS). However, few samples in the northern catchment show more positive delta H-2 values possibly due to increased evapo(transpi)ration by southward exposition and shallower soils there. The only small variability of delta H-2(C31) in the surface sediments is in the range of most topsoils delta H-2 from the catchment, and thus, well reflects local growing season precipitation. delta H-2(C23) in surface sediment samples from the central and deepest parts of the lake, that is, the lake's sediment accumulation zones, shows distinctly more positive delta H-2(C23) values due to evaporative lake water enrichment. Consequently, Delta(aq-terr), which is the isotopic offset between delta H-2(C23) and delta H-2(C31), indicates distinct lake water enrichment in the lake's accumulation zones and is a valuable proxy to investigate past hydrological changes.