Oliver R. Montagne, 88, of Jefferson, SD, passed away Thursday, January 30, 2025, surrounded by his family, at The Heritage at Northern Hills in Sioux City, IA. A Mass of Christian Burial will be held at 11:00 A.M. on Tuesday, February 4, 2025, at St. Peter’s Catholic Church in Jefferson, SD. Burial will be at St.Peter’s Catholic Cemetery. Visitation will be on Tuesday from 10:00 A.M. to 11:00 A…