Where is the upper Yellowstone valley fault located?

The Upper Yellowstone Valley Fault is a series of normal faults in the northern Rocky Mountains of the United States. The faults are located in southwestern Montana, just east of Yellowstone National Park. The faults trend north-south and have a total length of about 100 kilometers. The faults are thought to be the result of extensional tectonics in the region. The faults are part of the larger Yellowstone-Hebgen Lake earthquake zone, which is a region of high seismicity in the western United States.