Mossbrae Falls, Waterfall in Dunsmuir, California.

Mossbrae Falls is a waterfall in Dunsmuir, California, where spring-fed streams drop about 50 feet (15 m) over a moss-covered rock face into the Sacramento River. The falls are 175 feet (53 m) wide, with two especially large streams among many thinner ones. The upper cascades are hidden by plants; the bottom 50 feet is a straight plunge into the river.

The falls are fed by springs issuing from the canyon wall just south of Shasta Springs, a site developed as a resort in the late 19th century. The Union Pacific line along the Sacramento River runs through a cut beside the falls, and the city of Dunsmuir closed the illegal parking area in the Shasta Retreat neighbourhood in 2011. Two hikers were injured by trains there in 2011 and 2019, prompting a planned trail extension with a pedestrian bridge 1,800 feet from the falls.

The name joins words from Irish and Scottish language with the moss that covers the rock face along the river. Governor Arnold Schwarzenegger brought President George H.W. Bush here during a visit to Northern California.

The current route requires walking roughly 2.8 miles round trip along active railroad tracks, so authorities are working to establish an alternative trail. Visitors should remain alert for passing trains until an official footpath opens.

The water does not emerge from a single channel but rises from numerous parallel springs that bubble directly out of the porous rock face. The falls flow year-round with relatively steady intensity because they are fed by underground aquifers.