A minor earthquake was reportedly felt by people from Helena to Butte around 4:45 p.m. Saturday.
The epicenter of the 4.0 magnitude quake was about 10.5 miles south of Whitehall, according to preliminary information from the U.S. Geological Survey.
People in Helena, Butte, Whitehall and Pony reported to the USGS that they felt the earthquake. In some areas, respondents rated the shaking high enough to be felt by almost everyone indoors.
Though hundreds of small earthquakes are recorded in the region every year, Saturday's was one of the largest in the area so far in 2016, according to online USGS records.
Similar-sized quakes in the region include one that registered 4.3 on the Richter scale Jan. 30 about 12 miles east of Lincoln, and another that registered 4.3 on the Richter scale June 13 about 32 miles west of West Yellowstone.