The deal, which is expected to close in February, will be funded by existing credit facility, Legacy said.
Legacy said it will buy 13 operated oil fields in the Big Horn and Wind River Basins of Wyoming, and they produce 1,478 barrels of oil equivalent per day, of which 93 percent is oil.
Adding Wyoming as one of Legacy's core operating areas gives Legacy another geographic growth area and we expect this acquisition to be a springboard for additional acquisitions, Chief Executive Cary Brown said in a statement.
Units of Legacy rose 3 percent to a 52-week high of $19.50 Friday morning on Nasdaq. St. Mary Land shares were up 1.7 percent at $35.55 on the New York Stock Exchange. (Reporting by Arundhati Ramanathan in Bangalore; Editing by Deepak Kannan)