A subwavelength terahertz waveguide is presented in this article. The waveguide is made by cascading multiple planar split-ring resonators in one dimension. The structure can support magnetic plasmon propagation via induced oscillating currents along the chain. The simulation results show that the structure effectively transports energy at terahertz frequencies. A realization of this terahertz waveguide will lead to a wide range of applications, in particular on-chip terahertz communication channels.