Who Is Running for Uasin Gishu Senator in 2027?

Jackson Mandago (Senator, Uasin Gishu) of the United Democratic Alliance (UDA) holds the seat, and as of 23 September 2026 at least three people were preparing to take the UDA ticket from him before the 10 August 2027 election. The Star reported on 18 September 2026 that they were former county assembly speaker Isaac Terer, businessman Victor Chepkelat, and Kipchumba Isaac Nyongiot, known locally as the "Tuk-Tuk candidate".

Who holds the seat

Mandago was Uasin Gishu's first governor. He served two terms, from 2013 to 2022, and won the Senate seat in 2022. The Star reported that he chairs the Senate's health committee. His answer to the challengers was short: "When elections come, the great people of Uasin Gishu will decide."

The heaviest item in his record is the county's overseas education scheme. On 23 July 2026 a court in Nakuru acquitted Mandago and two former county officials of charges over about Sh1.1 billion collected from families for a study programme in Finland and Canada, finding that the prosecution had not proved its case, Kenyans.co.ke reported. The next day parents and students protested the acquittal in Eldoret, according to the Star, and families were still demanding refunds in late July, the Standard reported.

The challengers

Terer is running against Mandago's work as a senator. "We have had weak or no oversight on development programmes in Uasin Gishu," he told the Star, and added: "I have a clear plan, vision and will to serve the people of Uasin Gishu more efficiently and effectively." According to the paper, the challengers keep pointing to projects left unfinished from Mandago's years as governor, the Level 4 hospitals and the 64 Stadium among them.

Watching county spending is most of what a senator does. See how the Senate oversees counties for where that power starts and stops.

Why the UDA primary is the real contest

Uasin Gishu is in President William Ruto's home region and UDA dominates its politics. With every named aspirant going for the UDA ticket, the primary will probably settle the seat before polling day does. Parties must finish primaries by 8 May 2027 under the IEBC's gazetted calendar. If a result is disputed, challenging a primary result explains the route.

The governor's race is a UDA fight as well. Jonathan Bii (Governor, Uasin Gishu) faces Tourism PS Julius Bitok, businessman Bundotich Buzeki, Competition Authority director-general David Rotuk and trade chamber chair Willy Kenei, the Star reported on 17 August 2026. Bii's line was that "this county is locked until I complete my two terms". Whoever comes out ahead in that primary will shape which Senate aspirants find allies.

The county's politics has drawn national attention too. The NCIC summoned nominated MP Joseph Wainaina over remarks he made at Ngeria in Kapseret on 29 August 2026, the Star reported.

How the seat is decided

The senator is elected by the whole county on the same day as the governor, the woman representative, the MP and the MCA. The count starts on the polling-station Form 38A and ends in a declaration at county level. If you are fielding agents, read how the Senate count works on paper.

In a primary, turnout among members matters more than it does in the general election. Only people on UDA's membership list can vote in its primary, and parties must hand those lists to the Registrar by March 2027. An aspirant who has not signed up members by then is campaigning among people who cannot vote in the contest that decides the seat. See why the membership list is the real party.

Mandago has nine years as governor behind his name and a Senate seat to campaign from. Against him are the unfinished projects his rivals keep naming, and families still chasing refunds from the overseas study scheme, which the acquittal did nothing to settle.

What to watch

• Whether Mandago goes for the UDA ticket or another route.
• Whether the prosecution appeals the July 2026 acquittal. We found no report of an appeal as of 23 September 2026.
• Whether anyone outside UDA, from the Democracy for Citizens Party for example, enters.
• UDA's nomination rules, due for certification by the Registrar by 30 October 2026.