The 2006 United States Senate election in Wisconsin was held November 7, 2006. Incumbent Democratic U.S. Senator Herb Kohl won re-election to his fourth and final term in a landslide. As of 2025, this is the most recent state-wide election where any candidate won every county in Wisconsin.

Democratic primary

Candidates

Results

Republican primary

Candidates

Results

General election

Candidates

Predictions

Polling

Results

Counties that flipped Republican to Democratic

Analysis

Kohl won every county in the state. Kohl's weakest performance in the state was suburban Washington County, Wisconsin, which Kohl won with just 49.6%. Kohl's strongest performance was in rural Menominee County, where he won with over 90% of the vote. Vogeler's best performance was in Dane County, where she came in third place with over 5%, a county where Lorge had his second weakest performance.