This study details the fabrication and measurements of a water-filled 5 mm wide by 10 mm long silicon microheat pipe (MHP) array consisting of square channels. This study is unique in that many experimental results reported in open literature are for single channel microheat pipes. The number of channels in the array and the fluid charge used here were optimized under a separate study. A number of experiments were carried out on the specimen MHPs to determine their effective thermal conductivity and comparisons were made with previous results found in literature. The testing methodology was designed to remove systematic biases and the array thermal performance measurements are reported in terms of a silicon equivalence by identically measuring an uncharged empty silicon array as a baseline measurement. Two separate water-filled specimens were made, independently tested, and are reported to have thermal conductivities of and , representing a silicon equivalence of 1.8 and 2.2, respectively. All testing was performed in a horizontal orientation.