Two intersecting deformation fronts are observed in seismic reflection profiles in northeastern Eagle Plain, Yukon Territory. The most clearly defined triangle zone, along the southeast front of the Dave Lord fold-and-thrust belt, trends east-northeast in the vicinity of Porcupine River and includes rocks of the Eagle Plain Group of Late Cretaceous age. The tip line of the basal decollement lies within the Jurassic-Early Cretaceous succession. A generally north-south trending frontal zone on the west flank of the Richardson Mountains is more complicated than the Dave Lord triangle zone. In the north, the triangle zone geometry is similar to that of the Dave Lord zone; however, the basal decollement appears to detach within Upper Devonian rocks and ramps through the Mesozoic section near the leading edge. The identification of decollements beneath the west flank of the southern Richardson Mountains requires a reinterpretation of previous inferences that the range resulted from primarily vertical tectonics. An east-west crustal-scale cross-section shows 30% tectonic shortening by folding and thrust faulting across the range. Compressional strain is concentrated in areas where Paleozoic and Mesozoic shale troughs are exposed at the surface. Their underlying basement is likely weaker than the adjacent basement, contributing to strain localization. The competent basement and supracrustal succession of Porcupine Platform is less susceptible to shortening. The Richardson Anticlinorium is a north-south belt of localized shortening along a zone of crustal weakness and is repeatedly reactivated. The northeast-striking Dave Lord fold-and-thrust belt links shortening in the northern Ogilvie Mountains with shortening to the north and east in the northern Richardson Mountains. Its trend crosses the northern margin of Porcupine Platform but follows a proposed structural link between the Kandik Basin and the Blow Trough, two Cretaceous extensional basins.