Hyalite Peak-The mountain had been called Lost Mountain or Steamboat Mountain, and the creek Middle or Jackson Creek on some of the older maps. It is the gem from which the canyon gets its name, Hyalite, a colorless opal bubbling translucent from the edges of black volcanic rock, the aftermath of the area’s violent birth 43 millenniums before the upheavals that created the wonders in Yellowstone National Park. Under short wave ultraviolet light, it glows green and yellow.
In 1927 a petition was circulated by citizens of Gallatin County to have the Forest Service change the name of Middle Creek to something more distinctive. Since the peak at the head of the creek was called Hyalite, this was accepted and formalized by the Board on Geographic Names
Hyalite Reservoir is located 10.5 miles up Hyalite Canyon. The reservoir was constructed in the late 1940's and enlarged in 1993. It contains cutthroat trout and arctic grayling. A 'no wake' rule has been instituted, allowing only low speed motoring for trolling. Chisholm and Hood Creek Campgrounds are located on the east shore of the lake offering family camping units, picnic sites, boat ramps, outhouses, and drinking water.