We used 10x Genomics Chromium single-nucleus RNA sequencing to characterize the molecular diversity of brain cells across six developmental stages (from late fetal to aged adult) and four brain regions (prefrontal cortex, motor cortex, striatum, and thalamus) in the marmoset brain. Each developmental time point has 2 biological replicate donors, and each brain region has 2 technical replicates (10x reactions). Nuclei are NOT enriched (e.g., FACS sorted) for any particular population and contain neurons, glia, and vasculature populations.