Cedar Bog near Urbana in western Ohio is a protected fen, not a true bog, and one of the state’s most important surviving glacial wetlands. Only about 450 acres remain of an original landscape of roughly 7,000 acres. Formed after the Wisconsin glaciation retreated 12,000 to 18,000 years ago, it is sustained by mineral-rich groundwater filtering through deep gravel deposits above the buried course of the ancient Teays River. That unusual hydrology supports a cold-climate habitat with plants linked to Ice Age ecosystems and rare or endangered wildlife. Protected by the State of Ohio in 1942, it later gained national and state recognition for its natural significance.