Native T1 mapping is necessary for quantitative DCE-MRI of brain tumor and may have independent predictive value. Previous investigations using coarse spatial resolution have found tumor to have longer T1 compared to normal white matter. In this work, we evaluate a recent millimeter-resolution whole-brain T1 mapping approach in patients with high-grade glioma. T1 values in tumor and peritumoral regions were higher than that of normal white matter, consistent with literature. We also observed T1 spatial heterogeneity in these regions, further supporting the need for high resolution pre-contrast T1 mapping for quantitative DCE-MRI.