This dataset is from the PEX19-01 sediment record of Lake Peixão (40°20'35'' N, 7°36'19'' W), a small alpine lake located at 1677 meters above sea level in the Serra da Estrela Mountain, Portugal. Sediment cores were retrieved in June 2019 using a UWITEC piston coring system (Hernández et al., 2023). We adopt the age-depth model published by Hernández et al. (2023), which indicates continuous sedimentation over the past ~11,100 years. Moreover, we present XRF core-scanning elemental data and bulk organic matter (TOC, TN, δ¹³C and δ¹⁵N). XRF data were acquired at 5 mm resolution using an ITRAX scanner (rhodium tube; 30 kV, 30 mA, 30 s) at INRS Centre Eau Terre Environnement, Canada. Bulk organic matter analyses were measured at 4 cm intervals using a Flash IRMS EA IsoLink CNS elemental analyzer coupled to a DeltaV Advantage mass spectrometer (Thermo Scientific) at SAI-UDC, Spain. Isotopic values are reported against VPDB (carbon) and against atmospheric N₂ (nitrogen), with an analytical uncertainty of ± 0.15 ‰. The dataset was generated to reconstruct past hydroclimate and vegetation dynamics in Western Iberia.