Half Rock is an unincorporated community in Mercer County, in the U.S. state of Missouri. [1]
A post office called Half Rock was established in 1867 and remained in operation until 1900. [2] According to tradition, the community was derisively so named on account of the quality of the coffee at a nearby store (i.e. the coffee was "half rock".) [3] The community was never incorporated. [4]