ARMENCITA, the CARMENES Cool star Information and daTa Archive, is the M-dwarf database from where we will choose our best target sample. As part of our guaranteed time observations, about 300 late-type M dwarfs will be monitored by CARMENES from Calar Alto during over 600 nights. CARMENCITA currently catalogues over 2000 carefully-selected M dwarfs northern of delta > -23 deg. For each star, we tabulate dozens of parameters (accurate astrometry, spectral typing, photometry in 20 bands from the ultraviolet to the mid-infrared, rotational and radial velocities, X-ray count rates and hardness ratios, close and wide multiplicity data and many more) compiled from the literature or measured by us with new data. The private on-line catalogue, including preparatory science observations (i.e., high-resolution imaging, low- and high-resolution spectroscopy), will be eventually public as a CARMENES legacy.