Thin soil, cliff ledges, among boulders, waterlogged soil of late season snow melt. low to high elevations (0-2200 m). Greenland, Alta., B.C., N.B., Nfld. and Labr., N.W.T., Nunavut, Que., Yukon, Alaska, Colo., Maine, Mont., N.H., N.Y., Oreg., Wash., Europe, c, n Asia.
Conostomum tetragonum is easily recognized by its glaucous, stiffly erect leaves in five rows and apically connate peristome teeth. Philonotis seriata (known only from Greenland in the flora area), shares a pentastichous leaf arrangement with C. tetragonum, but the laminal cells of P. seriata are prorulose at the proximal ends and the peristome teeth are free.