This data set consists of isotopic and molecular information obtained from samples of particulate and dissolved organic matter collected throughout the ice-free season in the Lena River Delta, supplemented with samples from Central Siberian Rivers Kochechum and Nizhnyaya Tunguska.Particulate samples were obtained by filtering water through pre-combusted glass-fibre filters, dissolved organic matter was studied in the filtrate. Molar concentration ratios of organic carbon to nitrogen in particulate samples are additionally reported as well as stable carbon isotopic composition (δ13C in ‰ VPDB) and radiocarbon content (∆14C in ‰) of particulate and dissolved organic carbon.Concentrations of long-chain n-alkanes (n-C17 to n-C33) in suspended particulate matter samples collected on glass-fibre filters in the Lena Delta. The data set also contains stable hydrogen isotopic composition (δD) of odd-chain n-alkanes n-C23 to n-C31 expressed in permille relative to VSMOW.Contents of long-chain n-alkanes (n-C17 to n-C33) in soil samples as well as particles settled from a large-volume water sample collected in the Lena Delta. The data set also contains stable hydrogen isotopic composition (δD) of odd-chain n-alkanes n-C23 to n-C31 expressed in permille relative to VSMOW.