The 1978 Montana Senate election took place on November 7, 1978, with the primary election held on June 6, 1978. Montana voters elected 27 of the 50 members of the Montana Senate. The election coincided with United States national elections and Montana state elections, including U.S. Senate, U.S. House, and Montana House.
Following the previous election in 1976, the chamber was tied with both Democrats and Republicans holding 25 seats. Republicans flipped control of the chamber in 1978 by winning 26 seats while Democrats held 24—giving Republicans a net gain of one seat. The newly elected members served in the 46th Montana State Legislature, during which Republican William L. Mathers was elected President of the Montana Senate.
Retiring incumbents Democrats District 6: W. Gordon McOmber District 11: Joe R. Roberts District 19: John W. “Jack” Devine District 43: Robert E. "Bob" Lee District 46: Miles Romney
Incumbent defeated in primary election Democrat District 48: Elmer Flynn
Incumbents defeated in general election Democrats District 18: Margaret S. Warden District 40: Terry Murphy
Republicans District 15: Frank Dunkle District 36: L. M. “Larry” Aber District 50: William E. "Bill" Murray
Summary of results Italics denote an open seat held by the incumbent party; bold text denotes a gain for a party.
State senate district Incumbent Party Elected senator Outcome 4 Rep Rep hold 5 Rep Rep hold 6 Dem Rep gain 7 Rep Rep hold 9 Rep Rep hold 11 Dem Dem hold 14 Dem Dem hold 15 Rep Dem gain 18 Dem Rep gain 19 Dem Dem hold 22 Rep Rep hold 23 Rep Rep hold 25 Dem Dem hold 28 Rep Rep hold 31 Dem Dem hold 34 Dem Dem hold 35 Dem Dem hold 36 Rep Dem gain 37 Rep Rep hold 38 Dem Dem hold 40 Dem Rep gain 43 Dem Dem hold 44 Dem Dem hold 46 Dem Rep gain 47 Dem Dem hold 48 Dem Dem hold 50 Rep Dem gain
Detailed results by district District 4 • District 5 • District 6 • District 7 • District 9 • District 11 • District 14 • District 15 • District 18 • District 19 • District 22 • District 23 • District 25 • District 28 • District 31 • District 34 • District 35 • District 36 • District 37 • District 38 • District 40 • District 43 • District 44 • District 46 • District 47 • District 48 • District 50__NOTOC__
District 4
District 5
District 6
District 7
District 9
District 11
District 14
District 15
District 18
District 19
District 22
District 23
District 25
District 28
District 31
District 34
District 35
District 36
District 37
District 38
District 40
District 43 District 43 held a special election to fill the last two years of a vacated term.
District 44
District 46
District 47
District 48
District 50 District 50 held a special election to fill the last two years of a vacated term.
See also 1978 United States elections 1978 United States Senate election in Montana 1978 United States House of Representatives elections in Montana 1978 Montana House of Representatives election
References