Pulsating variable stars play an important role in the study of the Galaxy's history since they are excellent tracing populations in uniquely identifiable evolutionary phases. RR Lyrae stars, in particular, are known Population II objects that can also be used as precise distance indicators. These stars have been recently used to reveal the early assembly history of the Milky Way, since the early phases of massive galaxy evolution are believed to have been dominated by the accretion of smaller galaxies containing old stars. Moreover, they are thought to be potential tracers of faint satellite systems hardly detectable by the traditional methods. In this talk I will present the results from an RR Lyrae search using data from the High cadence Transient Survey (HiTS), which was carried out with the Dark Energy Camera (DECam). HiTS is a campaign primarily aimed at detecting early supernovae explosions in real-time with the deep optical images DECam provide. However, the cadence and the strategy followed for the survey are well matched for RR Lyrae detection as well. Using data from HiTS we were able to detect new RR Lyrae stars out to 200 kpc from the Sun. I will discuss the results of the search for RR Lyrae stars using HiTS’ data, their connection with known or previously undiscovered satellite systems and halo substructures, as well as further implications of these findings.