Epigenetic modifications parallel multiple memory processes, but evidence that the epigenetic makeup of a single site can guide learnt behaviors has so far been lacking. Here, we developed CRISPR-based epigenetic editing tools to address this question in a cell type-specific, locus-restricted and temporally controllable manner in the adult mouse brain. Focusing on learning-induced neuronal populations, we provide a proof-of-principle that site-specific epigenetic dynamics are causally implicated in memory expression.