Abstract: A handrail assembly and a handrail system incorporating the assembly. The handrail assembly includes a handrail which is a formed structure with an inner channel, and a mount structure accommodatable within the channel and having opposing substantially parallel members each having handrail engagement support members pliantly couplable with engagement support member acceptors within the channel. The handrail system incorporates the assembly and a base support structure extending from the mount structure. An expansive fill material can be introduced into the channel to substantially encapsulate the mount structure within the channel and provide protection from the environment. The handrail assembly provides a handrail structure and a mounting structure whereby the mounting structure is pliantly expandable and contractible to accommodate expansion non-compatibility of the mounting structure and the handrail structure due to temperature change.