The South American Summer Monsoon (SASM) is the main driver of regional hydroclimate variability across tropical and subtropical South America. It is best recorded on paleoclimatic timescales by stable oxygen isotope proxies, which are more spatially representative of regional hydroclimate than proxies for local precipitation alone. This data is presented as supplementary to a network study that characterizes SASM variability over the last millennium, separating the shared signal from local variability. Here, we present two new high-resolution samples (MV1, MV30) from the Mata Virgem cave (11°37′27.07′′S, 47°29′19.04′′W) located in the eastern region of the Brazilian tropical Savannah known as 'Cerrado'. The following parameters were collected from each stalagmite: δ¹⁸O, δ¹³C, and U/Th ages. More information about the Mata Virgem cave can be found in Azevedo et al. (2019).