RepublicanIn office since Nov 2022

Forrest J Mandeville

Montana State Senator, District 28 since 2022. Re-elected in 2026. Next on the ballot in 2030.

Montana State Senator, District 28Born 1984

Official website Wikipedia

In office: 3 yrs; Since 2022
Bills became law: 8; 21 sponsored, 2025–2026 session
Votes missed: 0.5%; Chamber median 0.5%
With party: 92%; On votes splitting the parties
Last margin: +37.0; Won 2026
Next election: 2030; Nov 5, 2030

Source: Wikidata, congress-legislators and Open States; 99chambers legislative recordsUpdated Oct 27, 2026, 1:51 PM ET

Committees

As of 2026-10.

General Government Interim Budget · vice chair
Local Government · chair
Local Government Interim · chair
Rules · vice chair
Education and Cultural Resources
Environmental Quality Council
Finance and Claims
Legislative Audit
Rules
School Funding Interim Commission

Source: Open States committeesUpdated Oct 27, 2026, 9:43 AM ET

Legislation

2025–2026 session · 21 sponsored · 8 became law

BillIntroCmteSenateHouseLaw

SB 174 Providing that recreational vehicles and mobile homes are reviewed as buildings for rent or lease
Landlord and Tenant · Became law May 2025

SB 532 Revise county zoning to allow accessory dwelling units
Counties · Became law May 2025

SB 121 Revise the land use and planning act
Cities and Towns · Became law May 2025

SB 262 Exempt subdivision, water/sewer plans from environmental review
Environmental Protection · Became law May 2025

SB 10 Extending onsite inspection timelines during state of emergency
Cities and Towns · Became law Apr 2025

Source: Open States billsUpdated Nov 6, 2026, 4:22 PM ET

Voting record

2025–2026 session · placement by roll-call votes

Where Mandeville sits in the Montana State Senate

Mandeville is closer to the center than 34% of the chamber's Republicans.

Closest: John Esp, Tom McGillvray, Ken Bogner

Source: 99chambers roll-call scalingUpdated Nov 6, 2026, 4:55 PM ET

With Mandeville’s party

Votes with the chamber's Republicans92%

Black tick: the average of Republicans in the Montana State Senate.

Source: 99chambers legislative scores from roll calls and cosponsorships

Key votes

Votes chosen for their effect, not their side: Mandeville’s vote, each party’s majority, and the result. An orange vote differs from most Republicans.

Date	Bill	Mandeville	Rep. majority	Dem. majority	Result
Apr 23, 2025	HB 860: Provide for veterinary training loan program	No	Yes	Yes	Passed 41–9
Apr 23, 2025	HB 129: Provide income tax benefit to support emergency response volunteers	No	No	Yes	Passed 28–22
Apr 23, 2025	HB 853: Revise fees for licensed establishments	Yes	No	Yes	Passed 29–21

Source: 99chambers key votes from Congress.gov, Voteview and Open States roll calls

Career

Offices held, and every time Mandeville was on a ballot. Filled marks are general elections won; hollow marks are primaries; an orange outline is a loss.

201420152016201720182019202020212022202320242025202620272028Montana House of Representatives, District 57 Montana State Senate, District 29

Source: 99chambers results archive (MEDSL, Klarner, state election offices)

Elections

Margin against the seat’s presidential baseline: how the seat voted for president in the same or nearest year.

Year	Race	Result	Margin	Seat	+/−
2026	Montana Senate District 28	Won	R+37.0	R+47.9	−10.9
2022	Montana State Senate, District 29	Won	—	—	—
2018	Montana House of Representatives, District 57	Won	—	—	—
2016	Montana House of Representatives, District 57	Won	R+70.1	—	—
2014	Montana House of Representatives, District 57	Won	R+57.7	—	—
2014	Montana House of Representatives, District 57 (primary)	Won	—	—	—