| |||||||||||||||||
| |||||||||||||||||
County results Boggs: 50–60% 60–70% | |||||||||||||||||
| |||||||||||||||||
The 1966 United States Senate election in Delaware took place on November 8, 1966. Incumbent Republican U.S. Senator J. Caleb Boggs was re-elected to a second term in office, defeating Democratic nominee James M. Tunnell Jr. As of 2024 [update] , this is the last time Republicans won Delaware's Class 2 Senate seat.
| Party | Candidate | Votes | % | ±% | |
|---|---|---|---|---|---|
| Republican | J. Caleb Boggs (incumbent) | 97,268 | 59.12% | ||
| Democratic | James M. Tunnell Jr. | 67,263 | 40.88% | ||
| Total votes | 164,531 | 100.00% | |||
| Republican hold | |||||