Mike Derby
South Dakota State Representative, District 34 since 1996. Re-elected in 2026. Next on the ballot in 2028.
- In office
- 30 yrs
- Since 1996
- Bills became law
- 0
- 7 sponsored, 2025–2026 session
- Votes missed
- 0.0%
- Chamber median 0.8%
- With party
- 61%
- On votes splitting the parties
- Last margin
- +3.6
- Won 2026
- Next election
- 2028
- Nov 7, 2028
Source: Wikidata, congress-legislators and Open States; 99chambers legislative recordsUpdated Oct 27, 2026, 1:51 PM ET
Committees
As of 2026-10.
- Appropriations · co-chair
- Appropriations · chair
- Developmental Disability Service Delivery
Source: Open States committeesUpdated Oct 27, 2026, 9:43 AM ET
Legislation
Appropriation · Failed in the Senate Mar 2026
Appropriation · Failed in the Senate Mar 2026
Appropriation · Failed in the House Feb 2026
Hoghouse-Vehicle Bill · Failed in the Senate Mar 2025
Hoghouse-Vehicle Bill · Failed in the Senate Mar 2025
Source: Open States billsUpdated Nov 6, 2026, 4:22 PM ET
Voting record
Where Derby sits in the South Dakota House of Representatives
Derby is closer to the center than 64% of the chamber's Republicans.
Closest: Tim Czmowski, Jack Kolbeck, Tim Walburg
Source: 99chambers roll-call scalingUpdated Nov 6, 2026, 5:01 PM ET
With Derby’s party
- Votes with the chamber's Republicans61%
Black tick: the average of Republicans in the South Dakota House of Representatives.
Source: 99chambers legislative scores from roll calls and cosponsorships
Key votes
Votes chosen for their effect, not their side: Derby’s vote, each party’s majority, and the result. An orange vote differs from most Republicans.
| Date | Bill | Derby | Rep. majority | Dem. majority | Result |
|---|---|---|---|---|---|
| Mar 30, 2026 | HB 1138: require the licensure of non-medical home care agencies, and to provide a penalty therefor. | Yes | Yes | Yes | Failed 36–27 |
| Mar 30, 2026 | HB 1077: consider a cultivated-protein food product to be adulterated food. | No | Yes | No | Failed 32–32 |
| Mar 9, 2026 | SB 245: create the homeowner property tax reduction fund, and to transfer moneys to the homeowner… | Yes | Yes | No | Passed 42–27 |
| Mar 5, 2026 | SB 159: revise requirements pertaining to the minimum age for marriage. | Yes | Yes | Yes | Passed 40–27 |
| Mar 5, 2026 | SB 179: permit a court to commit a juvenile adjudicated delinquent for certain weapons offenses to… | Yes | Yes | No | Passed 42–25 |
Source: 99chambers key votes from Congress.gov, Voteview and Open States roll calls
Career
Offices held, and every time Derby was on a ballot. Filled marks are general elections won; hollow marks are primaries; an orange outline is a loss.
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 | South Dakota Legislative District 34 | Won | R+3.6 | R+16.5 | −12.9 |
| 2024 | South Dakota House of Representatives, District 34 | Won | R+5.4 | — | — |
| 2022 | South Dakota House of Representatives, District 34 | Won | R+2.5 | — | — |
| 2020 | South Dakota House of Representatives, District 34 | Won | R+2.2 | — | — |
| 2000 | South Dakota House of Representatives, District 34 | Won | R+6.6 | — | — |
| 1998 | South Dakota House of Representatives, District 34 | Won | D+0.1 | — | — |
| 1996 | South Dakota House of Representatives, District 34 | Won | R+2.1 | — | — |
Source: 99chambers results archive; 2026: South Dakota Secretary of State (unofficial)Updated Nov 8, 2026, 7:01 PM ET
Campaign money, 2025–26
- Raised
- $88.4K
- Spent
- $84.7K
- Cash
- $9.5K
Source: South Dakota Secretary of State filings through Oct 20, 2026Updated Nov 1, 2026, 2:15 AM ET
Campaign committees
Open committees can still raise and spend money.
| Derby for State Representative District 34 State | Active |
Source: South Dakota Secretary of State filings through Oct 20, 2026Updated Nov 1, 2026, 2:15 AM ET
Seats Derby has held
- South Dakota House of Representatives, District 34 · since 2020
- South Dakota House of Representatives, District 34 · since 1996
Source: 99chambers results archive
Who Derby has run against
- Becky J. Drury (R) · 2026 general, won
- Heather Baxter (R) · 2024 election, won
- Jess Olson (R) · 2022 election, won
- Scott Eccarius (R) · 2000 election, won
Source: 99chambers results archive; 2026: South Dakota Secretary of State (unofficial)
How we know Derby
One person, matched across every source we use.
- Open States ocd-person/082e4c6e-c16a-4bfa-8c17-9c46952da446
- Wikidata Q104650634
Source: Identity links: Wikidata, congress-legislators, Open States, FECUpdated Oct 27, 2026, 1:51 PM ET