The Trillium class is a series of freighters owned by Canada Steamship Lines (CSL). The class is divided into three subclasses; the self-discharging lake freighters, the lake bulk carriers, and the Panamax self-discharging bulk carriers. Initially a nine-ship building program, six are operated by Canada Steamship Lines for use on the Great Lakes, while three are operated by CSL Americas for international trade. Two more ships were acquired later for use by CSL Americas.

Canada Steamship Lines (CSL) is a shipping company with headquarters in Montreal, Quebec, Canada. The business has been operating for well over a century and a half.