Blue Hole (Castalia)
The Blue Hole is a fresh water pond located in Castalia, Erie County, Ohio, in the United States. From the 1920s to 1990 the Blue Hole was a tourist site, attracting 165,000 visitors annually at the height of its popularity, partly because of its location on State Route 269, about southwest of the Cedar Point amusement park in Sandusky, Ohio.
Blue Mountains (ecoregion)
This ecoregion extends from the Redmond area of Central Oregon, across a wide swath of the Columbia Plateau in Eastern Oregon, to Hells Canyon on the Snake River at the border of the three states. The ecoregion is named for the Blue Mountains and contains a complex of basins and mountain ranges that, at average 2100-2900m, are lower and more open than the neighboring Cascades and Northern Rocky Mountains but do include some steep landscape of which Hells Canyon at 1,660m is North America's deepest gorge. The mountains of the ecoregion include the Strawberry Range, Greenhorn, Elkhorn, Aldrich and Maury Mountains in the Blue Mountains, the gentler Ochoco Mountains to the west and the rugged Wallowa Mountains to the east. Rivers include the Grande Ronde, Powder Rivers and Malheur Rivers, all tributaries of the Snake and the John Day and Umatilla Rivers, tributaries of the Columbia.