The Bull Lake glaciation is the name of a glacial period in North America that is part of the Quaternary Ice Age. The Bull Lake glaciation began about 200,000 years ago and ended about 130,000 years ago, and was concurrent with the Illinoian Stage of the Quaternary Ice Age. There is disagreement over these time frames, however, and further research is necessary. The Bull Lake Glaciation was followed by a warm interglacial period that lasted about 60,000 years. The Pinedale Glaciation, another local glacial period, occurred after this warm period.