flow of surface plasmons depending on the spin of the polarization of the excitation beam [@Zayats2014] or to spatially route the flow of photoluminescence (PL) depending on the spin of the polarization of the emitter transition [@Rauschenbeutel2014natcomm]. Such directional coupling, also known as chiral coupling, has been demonstrated in both the classical and in the quantum regimes [@Junge2013; @Lodhal2015; @GonzalezPRB2015; @Rauschenbeutel2015; @Young2015; @GonzalezPRA2016; @Coles2016]. Chiral coupling opens new opportunities in the field of light-matter interactions with the design of non-reciprocal devices, ultrafast optical switches, non destructive photon detector, and quantum memories and networks (see [@Zoller2016] and references therein).

In this letter, we propose a new platform consisting of spin-polarized valleys of a transition metal dichalcogenide (TMD) monolayer strongly coupled to a plasmonic OSO mode, at room temperature (RT). In this strong coupling regime, each spin-polarized valley exciton is hybridized with a single plasmon mode of specific momentum. The chiral nature of this interaction generates spin-momentum locked polaritonic states, which we will refer to with the portmanteau [*chiralitons*]{}. A striking feature of our platform is its capacity to induce RT robust valley contrasts, enabling the directional transport of chiralitons over micron scale distances. Interestingly, the strong coupling regime also yields coherent 