The de Longchamps line is central line with trilinear equation
(Droussent 1953; Kimberling 1998, p. 150) which is the anticomplement of the orthic axis (correcting the typo of Kimberling 1998, p. 150).
It is perpendicular to the Euler line at Kimberling center .
It passes through Kimberling centers for , 523, 684, 693, 850, 858, 1273, 1491, 2512, 2513, 2514, 2517, 3001, 3004, 3005, 3006, 3007, and 3014.
The de Longchamps line is the radical line of the coaxal system consisting of (anticomplementary circle, circumcircle, de Longchamps circle)