Presidential Strongholds: Where 90%+ of Voters Chose One Candidate

In Siaya, 98.93% voted for Raila Odinga in 2017. In Elgeyo/Marakwet, 96.86% voted for William Ruto in 2022. Kenya's presidential elections have strongholds where the outcome is never in doubt.

Every Kenyan election is really two elections happening at the same time. There are the strongholds, where the result is predetermined by ethnic and regional loyalty. And there are the swing counties, where the actual competition happens. The strongholds do not decide who wins. But they determine the margin. And in a 50%+1 system, margin is everything.

Let us look at the data from three elections to understand how strongholds work and whether they are changing.

The Most Extreme Results in Kenyan History

In the 2017 presidential election, the most extreme result was in Homa Bay, where Raila Odinga received 400,351 votes against Uhuru Kenyatta's 1,960. That is 99.51% for Odinga. Not 90%. Not 95%. Ninety-nine point five percent. In a county with 476,932 registered voters.

On the other side, Nyandarua gave Kenyatta 286,593 votes against Odinga's 2,286 in 2017. That is 99.21% for Kenyatta.

Here are the counties where the winner got 90%+ of valid votes across the 2017 and 2022 elections:

2017 — Odinga strongholds (above 90%):

• Homa Bay: 99.51% (400,351 vs 1,960)
• Siaya: 98.93% (375,712 vs 2,494)
• Kisumu: 97.32% (369,963 vs 7,411)
• Migori: 93.55% (274,161 vs 46,112) — Note: Kenyatta had some support here
• Vihiga: 91.38% (179,140 vs 18,275) — Note: some Jubilee votes here too

2017 — Kenyatta strongholds (above 90%):

• Nyandarua: 99.21% (286,593 vs 2,286)
• Kirinyaga: 98.61% (297,652 vs 3,120)
• Nyeri: 98.35% (389,410 vs 4,735)
• Murang'a: 97.86% (498,248 vs 9,122)
• Tharaka-Nithi: 94.02% (162,529 vs 10,355)
• Embu: 92.10% (231,350 vs 17,549)
• Kiambu: 92.62% (912,588 vs 69,190)

2022 — Ruto strongholds (above 90%):

• Elgeyo/Marakwet: 96.86% (160,033 vs 4,893)
• Bomet: 95.27% (285,428 vs 13,383)
• Nandi: 91.30% (280,813 vs 26,034)
• Kericho: 95.32% (318,861 vs 15,053) — Note: includes all candidates

2022 — Odinga strongholds (above 90%):

• Homa Bay: 98.93% (399,784 vs 3,497)
• Siaya: 98.60% (371,092 vs 4,320)
• Kisumu: 97.44% (419,997 vs 10,011)

Vote Share vs Turnout: The Scatter Plot

One of the most revealing analyses is to plot the winner's vote share against turnout. In strongholds, you see a distinctive pattern: very high vote share combined with relatively high turnout. When your candidate is running, you show up and you vote overwhelmingly for them.

The scatter plot for 2022 reveals several clusters:

• Top-right cluster (Ruto strongholds): Bomet, Kericho, Elgeyo/Marakwet, and Nandi with 90%+ vote share and 76-80% turnout
• Top-left cluster (Odinga strongholds): Siaya, Homa Bay, Kisumu with 97%+ vote share but turnout around 70-74%
• Middle band (competitive counties): Narok, Kajiado, Trans Nzoia where neither candidate dominated
• Low-turnout counties: Mombasa (44%), Kilifi (49%), Nairobi (56%) with moderate vote shares

The home region effect was strongest for the Rift Valley in 2022. Ruto's Kalenjin heartland counties turned out at high rates and voted overwhelmingly for him. This is the same pattern that Central Province showed for Kenyatta in 2013 and 2017.

Are Strongholds Shifting?

The short answer is: very slowly. Compare the Odinga strongholds across elections:

• Siaya: 92% turnout in 2013, 98.93% Odinga vote share in 2017, 98.60% in 2022 — rock solid
• Homa Bay: 94% turnout in 2013, 99.51% Odinga in 2017, 98.93% in 2022 — immovable
• Kisumu: 90% turnout in 2013, 97.32% Odinga in 2017, 97.44% in 2022 — actually increased slightly

Now compare the Central strongholds, which did shift:

• Kiambu: 91% turnout in 2013, 92.62% Kenyatta in 2017, then in 2022 Ruto got 73.49% (606,429 votes) while Odinga got 25.52% (210,580) — a significant change
• Murang'a: 97.86% Kenyatta in 2017 became 81.69% Ruto in 2022 — still a stronghold, but with more competition
• Nyeri: 98.35% Kenyatta in 2017 became 83.33% Ruto in 2022 — Ruto held it, but not as overwhelmingly

The lesson? When a candidate from the region is on the ballot, the stronghold is near-unanimous. When the candidate comes from outside, the stronghold still leans heavily but allows some competition. Central voted 90%+ for Kenyatta (their own) but "only" 73-84% for Ruto (an ally, but not from Central).

As political analysts have noted, this is the key dynamic for 2027. Without Kenyatta or Odinga on the ballot, traditional strongholds may show more competitive margins than Kenya has seen in decades.

The Political Math of Strongholds

Here is why strongholds matter mathematically. Ruto won 2022 by 233,211 votes. His Rift Valley strongholds alone — Bomet, Kericho, Nandi, and Elgeyo/Marakwet — gave him a combined margin of roughly 850,000 votes. Odinga's Nyanza strongholds of Siaya, Kisumu, and Homa Bay gave him about 1,150,000 votes in margin.

The election was not decided in these places. It was decided in Nairobi (+205,620 for Odinga), Kiambu (+395,849 for Ruto), Nakuru (+229,812 for Ruto), and the North Eastern counties. Strongholds provide the base. Swing counties provide the victory.

According to the Supreme Court's analysis of the 2022 petition, the geographic distribution of votes was one of the key factors examined when evaluating the legitimacy of the outcome.

What This Means for 2027

With the late Raila Odinga no longer on the ballot, the Nyanza stronghold dynamic changes fundamentally. Who inherits those near-unanimous margins? Can any Luo leader command 98% in Siaya? And with Ruto as the incumbent, will Rift Valley maintain its 2022 enthusiasm or will economic frustrations erode his base?

For more on how these patterns played out nationally, read the 2017 county-by-county results. For the turnout side of the equation, see the great turnout decline.

Key Takeaways

1. Siaya gave Odinga 98.93% in 2017 and 98.60% in 2022 — the most consistent stronghold in Kenya
2. Elgeyo/Marakwet gave Ruto 96.86% in 2022 — the strongest Kalenjin stronghold for the new president
3. Central's loyalty shifted — from 90%+ for Kenyatta to 73-84% for Ruto, still dominant but less monolithic
4. Strongholds provide the base; swing counties decide the winner
5. 2027 without Odinga or Kenyatta could reshape the stronghold map

Know your strongholds. Win the swing. Votrack provides polling-station-level vote share data across all three election cycles, helping campaigns understand exactly where their base is and where they need to compete. Request a demo for 2027 strategy.