Current tallies show Democrat Jon Tester leading the race for the U.S. Senate, but a Denny Rehberg spokesman says the Republican candidate has no intention of conceding.
Campaign Manager Erik Iverson says that votes are still being counted.
In the early hours of Wednesday morning, Rehberg had not yet made an appearance at his election party.
Rehberg campaign contributors, family and friends packed a convention room at the Billings Hotel shortly after the polls closed. Among the supporters present were notable Montana Republicans like former Senator Conrad Burns.
The crowd dwindled as the hours passed, but a couple of dozen supporters remained past midnight, watching numbers come in.