In order to accommodate high thermal loading of single-side-heated (SSH) components, robust thermal management and high-heat-flux-removal approaches are essential to prevent thermal instability, thermal runaway, or a thermal spiral toward component failure. This paper presents multidimensional steady-state heat transfer measurements for a high-strength-copper SSH monoblock (heat sink) coolant flow channel with a helical wire insert (HI) and thermally developing internal laminar and turbulent water (coolant) flow. In the present case, the term “monoblock” refers to a solid parallelepiped with a central coolant flow channel along the axial centerline. In addition to producing local two-dimensional (axial and circumferential) flow boiling curves, multidimensional monoblock wall temperature distribution comparisons were made between flow channels with and without a HI. Further, flow boiling curves were measured up to ~4.0 MW/m2 at the inside flow channel wall. For the same inside flow channel temperature, the HI enhanced (1) the incident heat flux by >70% when compared with the flow channel without the insert and (2) the inside flow channel wall heat flux by up to a factor of 5 near the monoblock heated side and at all axial locations. These results can be used for validation of computational fluid dynamics codes.