The analysis of lacustrine Pampean environmental archives is fundamental for reconstructing environmental and climatic fluctuations preceding instrumental measurements in the subtropical regions of South America. This chapter analyses results obtained from multiple set of paleolimnological studies in the Southwestern Pampa plain, in order to compare the hydrological response of lake systems to past atmospheric circulation variations linked to the southernmost influence of the South American Summer Monsoon. Analysed together, these reconstructions enable the identification and comparison of high and low-frequency climatic signals in the region. Additionally, they reveal how lake systems responded to climatic forcings during periods of low (e.g., Medieval Climate Anomaly, Little Ice Age) and high anthropogenic influence (Current Warm Period), placing the current variability within a broader timeframe than instrumental records provide. The joint analysis of these reconstructions allow us to identify regional and temporal patterns of the hydrological changes in the Southwestern Pampa plain during the Late Holocene, and compare them with other Pampean archives and paleoenvironmental records across the continent.