Grandglaize Creek is a creek and tributary to the Osage River that forms the Grand Glaize Arm of the Lake of the Ozarks in Missouri. The creek flows for 10 miles (16 km) before reaching the Lake of the Ozarks, and the Grand Glaize Arm extends another 15 miles (24 km) before reaching the Osage River within the lake.
The creek as recognized by the Geographic Names Information System (GNIS) is spelled as one word. However it is widely spelled as two words Grand Glaize. It should not be confused with the Grand Glaize Creek which is a tributary to the Meramec River in St. Louis County, Missouri.
The creek is formed by the confluence of Dry Auglaize Creek and Wet Glaize Creek near Brumley, Missouri near Toronto, Missouri in Camden County, Missouri. From there it flows north through Miller County, Missouri,
According to the Missouri Department of Natural Resources the lowest flow that could be expected in a 10-day period is 16 cubic feet (0.45 m3) a second The creek becomes part of the Lake of the Ozarks at the extreme southeast corner of Lake of the Ozarks State Park.
When Bagnell Dam was built to impounded the Osage River, it also impounded the creek which had previously flowed into the river. The Grand Glaize Bridge carried U.S. Highway 54 over what is now the Grand Glaize arm of the lake. The bridge was known as the "Upside-Down Bridge" because the supporting structure was built below the deck to allow for an unobstructed view of the lake. The bridge was infamous for having very narrow lanes, no shoulders, and steel railings (which one could still see the lake through) as barriers. The bridge was replaced in the 1980s, when a wider bridge was constructed next to it. The new bridge carried Highway 54 and the old bridge was restricted to bicycles and pedestrians. In the 1990s, the original bridge was demolished and replaced with a new bridge to carry two lanes of westbound Highway 54. The 1980s bridge was changed to carry two lanes of eastbound Highway 54.