Colorado's US Senators
```mediawiki Colorado is represented in the United States Senate by two senators, both Democrats as of 2025: Michael Bennet, who has served since his appointment in January 2009, and John Hickenlooper, elected in 2020 after serving as Colorado's governor. As with all states, Colorado elects two senators to six-year terms in the upper chamber of Congress, with staggered elections ensuring that one-third of the Senate stands for election every two years. Colorado's senators have increasingly focused on water rights, public lands management, military installations, and emerging technology and energy policy—priorities shaped by the state's distinctive geography and a growing population that reached approximately 5.8 million by the early 2020s.
History
Colorado's participation in the United States Senate dates to the state's admission to the Union on August 1, 1876, as the 38th state. The state was granted immediate representation in the Senate through the election of its first two senators, Henry Moore Teller and Jerome B. Chaffee, who were selected by the Colorado Legislature—a common practice before the ratification of the Seventeenth Amendment in 1913, which established direct popular election of senators.[1] Teller, a Republican, served two nonconsecutive terms and became closely identified with the free silver movement, a cause that held enormous political weight in Colorado during the silver and gold mining era.[2] Other notable early senators included Edward Oliver Wolcott and Thomas M. Patterson, whose careers reflected the state's evolving political alignments and the economic dominance of the extractive industries.
The transition to direct election of senators in the early twentieth century shifted how Coloradans influenced their representation in Washington. During the mid-twentieth century, Republican Eugene Millikin served from 1941 to 1957 and held senior positions on the Senate Finance Committee, making him one of the more influential members of the chamber during his tenure.[3] The latter part of the twentieth century brought senators who addressed issues central to Colorado's development, including water rights, natural resource management, and defense spending tied to the state's major military installations.
Colorado's Senate delegation took on a more nationally prominent character in the 1970s and 1980s. Gary Hart, elected in 1974 on the coattails of post-Watergate Democratic gains, became a significant figure in defense reform and eventually a presidential candidate. Tim Wirth, who served from 1987 to 1993, was among the early Senate voices on climate change. Ben Nighthorse Campbell made history as one of the few Native Americans to serve in the U.S. Senate; elected as a Democrat in 1992, he switched to the Republican Party in 1995 and served until 2005.[4] The party switch illustrated the broader rightward movement then underway in Colorado's rural and western communities, even as the state's suburban Front Range counties were beginning to trend in the opposite direction.
Republican Wayne Allard held one of Colorado's Senate seats from 1997 to 2009, when he was succeeded by Michael Bennet following the appointment process triggered by Ken Salazar's departure to serve as Secretary of the Interior in the Obama administration. Colorado's shift from reliably Republican to consistently competitive—and more recently to a state where Democrats have won every statewide Senate election since 2008—reflects the growth of the Denver metropolitan area, rising educational attainment, and substantial demographic change across the Front Range.[5]
Current Senators
Michael Bennet
Michael Bennet was appointed to the Senate in January 2009 by Governor Bill Ritter to fill the seat vacated by Ken Salazar and has since won reelection in 2010, 2016, and 2022. Before his Senate appointment, Bennet served as superintendent of Denver Public Schools. He sits on the Senate Finance Committee and the Senate Agriculture, Nutrition, and Forestry Committee, assignments that directly engage with two of Colorado's central economic concerns: federal tax and trade policy, and the agricultural economy of the Eastern Plains and mountain valleys.[6]
Bennet has been a vocal advocate for Colorado's water interests within the Senate. He has worked on legislation addressing Colorado River compact negotiations and drought contingency planning across the seven-state basin. In December 2025, Bennet placed a hold on a federal appropriations package in an effort to block the Trump administration's plans to dismantle the National Center for Atmospheric Research (NCAR) in Boulder, a federally funded climate and weather research institution operated by the University Corporation for Atmospheric Research.[7] The hold drew criticism from some quarters as prioritizing a single Boulder institution over broader federal funding needs, but Bennet and his office defended it as necessary to protect a research center employing hundreds of scientists and generating data used by federal weather and emergency management agencies.[8]
John Hickenlooper
John Hickenlooper was elected to the Senate in November 2020, defeating incumbent Republican Senator Cory Gardner by approximately 9 percentage points. Before his Senate career, Hickenlooper served two terms as Colorado's governor (2011–2019) and before that as mayor of Denver (2003–2011). He is a geologist by training and built a career as a brewpub entrepreneur in Lower Downtown Denver before entering politics. In the Senate, Hickenlooper serves on the Commerce, Science, and Transportation Committee and the Health, Education, Labor, and Pensions (HELP) Committee.[9]
Hickenlooper joined Bennet in the December 2025 effort to protect NCAR, placing a coordinated hold on the same appropriations legislation and arguing that the administration's proposed elimination of the center would cost Colorado hundreds of research jobs and undermine national weather forecasting capacity.[10] The two senators also joined a Senate investigation into a new EPA rulemaking process, raising concerns about the environmental review procedures for regulations affecting Colorado's air quality and water resources.[11]
List of Colorado U.S. Senators
The following table lists individuals who have served as United States Senators from Colorado since statehood in 1876.
| Senator | Party | Years of Service | Notes |
|---|---|---|---|
| Jerome B. Chaffee | Republican | 1876–1879 | One of Colorado's first two senators |
| Henry Moore Teller | Republican / Silver Republican | 1876–1882, 1885–1909 | Advocate of free silver coinage |
| Edward Oliver Wolcott | Republican | 1889–1901 | |
| Thomas M. Patterson | Democrat | 1901–1907 | Newspaper publisher and attorney |
| Charles J. Hughes Jr. | Democrat | 1909–1911 | |
| John F. Shafroth | Democrat | 1913–1919 | Former Colorado governor |
| Lawrence C. Phipps | Republican | 1919–1931 | |
| Alva Adams | Democrat | 1923–1924 | |
| Karl C. Schuyler | Republican | 1932–1933 | |
| Walter Walker | Democrat | 1932–1933 | |
| Edward P. Costigan | Democrat | 1931–1937 | |
| Edwin C. Johnson | Democrat | 1937–1955 | Also served as governor |
| Eugene D. Millikin | Republican | 1941–1957 | Senior member, Senate Finance Committee |
| Gordon Allott | Republican | 1955–1973 | |
| John A. Carroll | Democrat | 1957–1963 | |
| Peter H. Dominick | Republican | 1963–1975 | |
| Floyd K. Haskell | Democrat | 1973–1979 | |
| Gary Hart | Democrat | 1975–1987 | Presidential candidate, 1984 and 1988 |
| William L. Armstrong | Republican | 1979–1991 | |
| Tim Wirth | Democrat | 1987–1993 | Early Senate voice on climate change |
| Hank Brown | Republican | 1991–1997 | |
| Ben Nighthorse Campbell | Democrat / Republican | 1993–2005 | Switched parties in 1995; one of few Native Americans to serve in the Senate |
| Wayne Allard | Republican | 1997–2009 | |
| Ken Salazar | Democrat | 2005–2009 | Resigned to serve as Secretary of the Interior |
| Mark Udall | Democrat | 2009–2015 | |
| Michael Bennet | Democrat | 2009–present | Appointed 2009; elected 2010, 2016, 2022 |
| Cory Gardner | Republican | 2015–2021 | |
| John Hickenlooper | Democrat | 2021–present | Former governor and mayor of Denver |
Current Responsibilities and Representation
Colorado's two senators serve as the primary federal representatives for the state's approximately 5.8 million residents, handling constituent services, introducing legislation, and sitting on Senate committees that address matters directly relevant to the state.[12] Water policy is among the most enduring and consequential focuses for the delegation. Colorado sits at the headwaters of the Colorado River and several other major western river systems, and the state's senators engage regularly with the Senate Energy and Natural Resources Committee on water compacts, drought management, and the long-running negotiations among the seven Colorado River basin states. The federal government controls approximately 36 percent of land in Colorado, encompassing national forests, national parks, and Bureau of Land Management properties, which means public lands management is never far from the senators' legislative calendars.
Colorado hosts significant military infrastructure. Fort Carson near Colorado Springs is one of the Army's largest installations, Buckley Space Force Base in Aurora supports space operations and intelligence missions, and the U.S. Air Force Academy sits just north of Colorado Springs. Defense appropriations and military quality-of-life legislation are therefore standing priorities for both senators, who work to protect and expand the state's military presence.[13] The state's higher education institutions—including the University of Colorado system, Colorado State University, and the Colorado School of Mines—rely substantially on federal research grants, and Colorado's senators frequently intervene to protect that funding stream, as demonstrated by the 2025 NCAR dispute.
The state's economy spans extractive industries with roots in the 19th century and technology sectors that emerged in the late 20th and early 21st centuries. Oil and gas production on the Eastern Slope and in the Piceance Basin makes energy regulation a live issue; so does the state's rapidly growing renewable energy sector. Boulder, Denver, and the broader Front Range corridor have attracted software, aerospace, and defense technology companies, drawing the senators into debates over cybersecurity policy, broadband deployment, and federal research and development spending. These overlapping and sometimes competing economic interests mean Colorado's senators must balance constituencies with sharply different views on regulation, public lands access, and the pace of the energy transition.
Committee Work and Legislative Influence
The committee assignments held by Colorado's senators shape much of their day-to-day legislative work. Michael Bennet's seat on the Senate Finance Committee gives him a direct role in tax legislation, trade agreements, and Medicare and Medicaid funding—federal programs with substantial reach into Colorado's economy and health care system. His Agriculture Committee assignment positions him to address crop insurance, conservation programs, and rural development funding for Colorado's farming communities on the Eastern Plains. Hickenlooper's Commerce Committee assignment touches on technology regulation, transportation infrastructure, and consumer protection, areas of growing importance to Colorado's Front Range economy. His HELP Committee work engages with workforce training, education funding, and pharmaceutical regulation.[14]
Bipartisan cooperation on western water issues and public lands management has historically been easier to achieve than on other legislative fronts, because the stakes are regional rather than strictly partisan. Colorado senators have worked with counterparts from Arizona, Nevada, Utah, and other western states on Colorado River compact compliance, drought contingency planning, and wildfire management policy. That tradition of western-states collaboration has persisted even as the broader Senate has become more polarized. The December 2025 appropriations standoff over NCAR was a pointed illustration of how Colorado's senators use procedural tools—specifically, the senatorial hold—to protect specific state interests, though the tactic drew editorial criticism questioning whether it appropriately balanced parochial and national considerations.[15]
Campaign Finance
Colorado Senate campaigns have attracted substantial national funding, reflecting the state's competitive status. Both Bennet and Hickenlooper have raised and spent tens of millions of dollars across their campaigns. Hickenlooper's 2020 race against Cory Gardner was among the most expensive Senate contests in the country that cycle, with combined candidate and outside spending exceeding $100 million. Detailed contribution data—including breakdowns by industry, PAC, and individual donor—are tracked by the Center for Responsive Politics through its OpenSecrets platform, which draws on Federal Election Commission filings.<ref>{{cite web |title=Michael Bennet Campaign Finance Summary |url=https://www.opensecrets.org/members-of-congress/michael-bennet/summary |work=OpenSecrets |access-date=2026-02-26