The epigenetic determinants driving the rapid responses of memory CD4 T cells to antigen are currently an area of active research. While much has been done to characterize various Th subsets and their associated genome-wide epigenetic patterns, the dynamics of histone modifications during CD4 T cell activation and the differential kinetics of these epigenetic marks between naïve and memory T cells have not been evaluated. In this study we have detailed the dynamics of genome-wide promoter H3K4me2 and H3K4me3 over a time course during activation of human naïve and memory CD4 T cells. Our results demonstrate that changes to H3K4 methylation predominantly occur relatively late after activation (120 hours) and reinforce activation-induced upregulation of gene expression affecting multiple pathways important to T cell activation, differentiation, and function. The dynamics and mapped pathways of H3K4 methylation are distinctly different in memory cells. Memory CD4 have substantially more promoters marked by H3K4me3 alone, and that is influenced by promoter CpG content, reinforcing their more differentiated state. Our study provides the first data examining genome-wide histone modification dynamics during T cell activation, providing insight into the cross-talk between H3K4 methylation and gene expression, and underscoring the impact of these marks upon key pathways integral to CD4 T cell activation and function. RNA-Seq of naïve and memory CD4 T cells at rest and at 3 time points after activation with anti-CD3/CD28.