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A Lagrange point is a stationary position in the rotating frame of the circular restricted three-body problem. The two primaries' gravitational forces and the centrifugal force balance there. Their gravitational pulls alone need not cancel.

Three Collinear Lagrange points lie on the line through the primaries; two Triangular Lagrange points complete equilateral triangles with them. Stability requires the full rotating-frame equations, including the Coriolis force. The collinear equilibria are unstable, while the triangular equilibria are linearly stable for a sufficiently small secondary mass fraction. Spacecraft can use nearby trajectories with stationkeeping; an equilibrium calculation alone does not make a spacecraft remain there.^[ref]

Neil J. Cornish authored an explanation of Lagrange points, the rotating-frame equilibrium locations of a restricted three-body problem. The exposition distinguishes balancing at an equilibrium from dynamical stability near it.^[ref]