We combine Spitzer and ground-based KMTNet microlensing observations to identify and precisely measure an Earth-mass (1.32+0.41−0.28M⊕) planet OGLE-2016-BLG-1195Lb at 1.11+0.13−0.10 AU orbiting a 0.072+0.014−0.010M⊙ ultracool dwarf, likely a brown dwarf. […]