South Dakota 2026 SENATE FORECAST

2026 South Dakota Senate Forecast:

The Pollsmax 2026 South Dakota Senate forecast currently gives Republican Mike Rounds a 98.5% chance of defeating independent Brian Bengs. Pollsmax projects Rounds to receive 58.5% of the vote compared with 41.5% for Bengs, a projected Republican margin of 17 percentage points. The model currently rates the race as Solid Republican. The forecast is updated using 100,000 simulations incorporating polling and race fundamentals. See the Pollsmax forecast methodology.

The 2026 South Dakota Senate election features independent Brian Bengs and Republican Mike Rounds. Incumbent Senator Mike Rounds is seeking reelection to a third full term, having served in the US Senate since 2015. In 2024, Donald Trump won South Dakota by a landslide, and Republicans are expected to easily retain the state's Senate seat in 2026. The race will test whether Bengs can assemble an independent coalition or whether Rounds can win another comfortable term. South Dakota is expected to remain safely Republican as the GOP works to preserve control of the US Senate.