Alligator Lake is an alkaline volcanic centre located in southern Yukon, Canada. It occurs at the northern extremity of the Stikine volcanic belt, belonging to the North Cordilleran Volcanic Province. Structurally, it is composed of two cinder cones capping a small shield volcano formed of a basaltic succession. Country rocks belong to the granitoid Cretaceous Coast Plutonic Complex and the Tertiary Skukum Volcanic Group. Lava flows, cinder cones and scoria are composed of alkali olivine basalt, basanite, and tholeiitic basalt and are found ~5 km north west of the northern protrusion of the lake. Basanite contains normative nepheline (2.2-6.3%) and flows often include xenoliths of country rock granite and spinel lherzolite along with olivine, pyroxene, and spinel megacrysts. Petrography, Sr-Nd isotopic data, and whole rock major and trace element data can be found in Eiché et al. (1987).