LHS 1815 is a cool M-dwarf (about 0.50 solar masses, 3,643 K, 0.50 solar radii), 29.8 light-years from Earth. LHS 1815 b is a 1.6-Earth-mass planet, with an orbital period of 3.8 days, discovered in 2020 via transit. The planet was found when it crossed the face of its star, producing periodic dips in brightness that reveal its size and orbital period to space-based photometry. At 1.1 Earth radii, LHS 1815 b is a compact world comparable in size to rocky planets in our Solar System.