Yellowstone Lake

Yellowstone Lake in the southern part of the park is a large body of water, covering 136 square miles. The road follows the 110 mile shoreline for quite a ways. When we were there, it was windy and sometimes drizzling and we saw one sailboat out. Supposedly, there are hot springs that feed the middle of the lake. The deepest spot is almost 400 feet deep. Still, the lake freezes solid to a depth of over three feet every December and may not thaw until June.

I found this historic photograph of Yellowstone Lake. It was one of the first taken, printed in 1878. The photographer was William Henry Jackson who was part of the first geological survey team sent to the area.  His photographs of Yellowstone helped convince Congress to designate it the first National Park in 1872. 

The  information below from Wikipedia gives insight to the difficulties of producing this picture:

Jackson worked in multiple camera and plate sizes, under conditions that were often incredibly difficult.^[3] His photography was based on the collodion process invented in 1848 and published in 1851 by Frederick Scott Archer. Jackson traveled with as many as three camera-types—a stereographic camera (for stereoscope cards), a "whole-plate" or 8x10" plate-size camera, and one even larger, as large as 18x22". These cameras required fragile, heavy glass plates (photographic plates), which had to be coated, exposed, and developed onsite, before the wet-collodion emulsion dried. Without light metering equipment or sure emulsion speeds, exposure times required inspired guesswork, between five seconds and twenty minutes depending on light conditions.

Preparing, exposing, developing, fixing, washing then drying a single image could take the better part of an hour. Washing the plates in 160 °F hot spring water cut the drying time by more than half, while using water from snow melted and warmed in his hands slowed down the processing substantially. His photographic division of 5-7 men carried photographic equipment on the backs of mules and rifles on their shoulders. Jackson's life experience (for example his military service, and his peaceful dealings with Indians) was welcomed. The weight of the glass plates and the portable darkroom limited the number of possible exposures on any one trip, and these images were taken in primitive, roadless, and physically challenging conditions. Once when the mule lost its footing, Jackson lost a month's work, having to return to untracked Rocky Mountain landscapes to remake the pictures, one of which was his celebrated view of the Mount of the Holy Cross