2018Final results
2018 election for Colorado's 4th District
U.S. House · Colorado
Ken Buck (R) won with 60.6% of the vote, defeating Karen McCormick (D) by 21.2 points.
Ken BuckRepublican · winner
60.6%224,038
Karen McCormickDemocrat
39.4%145,544
369,620 votes
Source: MIT Election Data and Science LabUpdated Oct 1, 2026, 6:17 AM ET
The seat over time
D − R margin in this seat's races around 2018
Races before and after
Source: MIT Election Data and Science LabUpdated Oct 1, 2026, 6:17 AM ET
Money in this race
Each line compares the two campaigns on one scale.
Karen McCormickKen Buck
$976.1K
Raised by the campaign
$615.3K
$952.9K
Spent by the campaign
$665.2K
$23.2K
Cash on hand
$351.1K
Campaign money: FEC, through Dec 31, 2018.
Source: FEC campaign filingsUpdated Dec 31, 2018