Notes. Elements are obtained from the precessing ellipse model (e.g., Jacobson 2009) fitted to the integrated orbit of each satellite over the 400-yeartime span from 1800 January 1 to 2200 January 1. The orbit is planetocentric for Triton, but for the far more distant Nereid, the orbit has a focus located at the Neptunian system barycenter. Listed elements are semimajor axis, a, eccentricity, e, inclination, i, mean longitude, λ, longitude of periapsis, ϖ, longitude of the ascending node, Ω, mean longitude rate, , rate of apsidal precession, , and rate of nodal precession, . The right ascension and declination of Laplace plane pole referred to the ICRS are α_Lap and δ_Lap, respectively. The orbital longitudes are measured from the intersection of the Laplace plane with the ICRS reference plane. Because Triton orbit is retrograde, λ = M − ϖ and ϖ = Ω − ω, where M is the mean anomaly and ω is the argument of periapsis; for Nereid, λ = M + ϖ and ϖ = Ω + ω.