The lanthanide orthoborates, $Ln$BO$3$, $Ln$ = Gd, Tb, Dy, Ho, Er, Yb crystallise in a monoclinic structure with the magnetic $Ln3+$ forming an edge-sharing triangular lattice. The triangles are scalene, however all deviations from the ideal equilateral geometry are less than 1.5%. The bulk magnetic properties are studied using magnetic susceptibility, specific heat and isothermal magnetisation measurements. Heat capacity measurements show ordering features at $T\le$ 2 K for $Ln$ = Gd, Tb, Dy, Er. No ordering is observed for YbBO$3$ at $T\ge$ 0.4 K and HoBO$3$ is proposed to have a non-magnetic singlet state. Isothermal magnetisation measurements indicate isotropic Gd$\mathrm{<mrow\; data-mjx-texclass="ORD">3+</mrow>}$ spins and strong single-ion anisotropy for the other $Ln3+$. The change in magnetic entropy has been evaluated to determine the magnetocaloric effect in these materials. GdBO$3$ and DyBO$3$ are found to be competitive magnetocaloric materials in the liquid helium temperature regime.