Blelham Tarn is a large valley tarn in the Lake District of England, to the north of the hill Latterbarrow. The settlements of , Low Wray and High Wray are close by. The tarn is drained to the northeast by the short into Windermere. This beck was previously straightened and lowered.Fish species in the tarn include brown trout, eel, perch, pike and roach, much of the tarn shore is reedbed and waterfowl present can include great crested grebe, whooper swan and golden-eye.