Rosemary M. Collyer, a federal district court judge in the District of Columbia who was highly regarded for her trailblazing career as a woman in the law and government, died on June 7, 2026, in Rockville, Maryland, after a long illness. She was 80.

Before joining the U.S. District Court of D.C. in 2003, Collyer was the first woman to chair the Federal Mine Safety and Health Review Commission, serve as general counsel of the National Labor Relations Board, and chair the management committee of a prominent Washington, D.C., law firm.  Along the way, she mentored younger lawyers and jurists and maintained a humility that drew the respect of those around her.

“One of her skills was she was not so taken with herself. She didn’t pretend she knew everything while in front of the lawyers,” said Senior Judge Thomas F. Hogan, who was the court’s chief judge when Collyer joined. She also gained a reputation for her well written, carefully reasoned rulings, he said. “She made her mark.”

On the court, she ruled on a range of high-profile cases on voting rights, the constitutional power of the purse, the U.S. military’s drone killings of Americans in Yemen, and more. She also served as presiding judge of the Foreign Intelligence Surveillance Court (FISC), handling the oversight of surveillance of Carter Page, a Trump campaign adviser suspected of colluding with Russian government officials.

Rosemary Elizabeth (Mayers) Collyer was born on November 19, 1945, in Port Chester, New York, the eighth of nine children of Thomas C. Mayers and Alice M. Henry. She spent most of her childhood in Stamford, Connecticut, where her father was elected mayor in 1963. A Republican who rode into office with Democratic support, Mayers pushed for a progressive urban renewal plan and expanded civil rights. He firmly backed a plan that would have scattered low-income housing through Stamford even though it earned him animosity from many White middle-class voters and cost him his second reelection bid. Mayers’ strong human rights convictions and life lessons made a deep impression on his talented daughter.

In 1968, Collyer graduated cum laude with a bachelor’s degree in history from Trinity College in Washington, D.C. (now called Trinity Washington College). Three weeks after graduation, she married Philip L. Collyer. The two had met in junior high school and started dating when she was sixteen. “His importance goes to my genes and the entire warp and woof of my life,” she once said. After living and working various jobs in Canada, New York, and then Colorado, colleagues convinced her to try law school.

In 1974, Collyer began studying in the evenings at the University of Denver Law School (now Sturm College of Law), just months before giving birth to their son, Timothy. She immediately took to her studies while juggling coursework and internships, amid duties of motherhood, and graduated eighth in her class in 1976.

Collyer began her law career as a labor lawyer at Sherman & Howard LLC in Denver, primarily representing Colorado mining companies. She fearlessly clambered underground into mining shafts to better understand the requirements and effects of new mine safety laws. In 1981, the Reagan administration brought her to Washington to serve as chair of the Federal Mine Safety and Health Review Commission. The Senate swiftly confirmed her nomination.

Less than three years later, President Reagan nominated her to be general counsel for the NLRB. She was thirty-nine. Democrats and labor union executives harshly challenged her during confirmation hearings that fall. Ultimately, Reagan granted her a recess appointment and, after he won reelection, the Senate confirmed her nomination.

She soon surprised many observers with her handling of a major labor dispute involving a work contract that General Motors and the United Auto Workers had reached for a new manufacturing plant to build the Saturn automobile. Her ruling against the National Right to Work Committee, allowing the union’s work contract to go forward, earned her the respect of labor leaders.

In 1989, at the end of her term, Collyer joined the law firm of Crowell & Moring LLP in Washington DC, where she notably represented Greyhound Bus Lines during a multiyear labor strike. In 1995, she was elected the first woman chair of the firm’s management committee.

In spring 2002, when proposing to President George W. Bush that he nominate Collyer to be a district judge, White House aides noted that Collyer had demonstrated at the NLRB a “sound philosophy of restraint” and had “shown herself capable of reaching results through a disciplined application of the law that are contrary to her own political philosophy.” Her Senate confirmation proceeded smoothly, and she became just the eighth woman to serve on the court.

More than a dozen years later, TheWall Street Journal wrote that while Collyer was not a household name, most people had heard of her decisions. In March 2005, during the Global War on Terrorism, she blocked the transfer of thirteen detainees held at Guantanamo to Yemen because it would take them outside the court’s jurisdiction. She wrote that “no free man should be imprisoned, dispossessed, outlawed, or exiled save by the judgment of his peers or by the law of the land.” Also in 2005, she blocked a Bush administration plan governing employees of the newly formed Department of Homeland Security because it would disadvantage workers. She explained that “collective bargaining would be on quicksand.” In 2012, as part of a three-judge panel, she voted with the majority to reject Texas’ voter identification law because of its impact on poor and minority voters.

In 2015, Collyer permitted the U.S. House of Representatives to proceed with a lawsuit against the executive branch over Affordable Care Act spending. It was the first time a chamber in Congress had sued the executive branch. She wrote that the House “had a core constitutional interest in preserving its power of the purse.” The next year, she upheld a challenge to the government’s designation of insurer MetLife as “too big to fail” that had put the company under heightened government scrutiny.

From the bench, she sought to mentor other women in the courtroom. D.C. Superior Court Judge Darlene M. Soltys had served as an assistant U.S. attorney and appeared before Collyer in several trials related to the M Street Crew, a notorious drug gang in Northeast Washington. At the unveiling of Collyer’s judicial portrait in 2017, Soltys said Collyer “had high expectations that women appearing in her courtroom would perform as well as, if not better, than any male attorney.” At the same ceremony, Judge Beryl A. Howell said Collyer immediately served as a mentor at the district court. Collyer was “a go-to sounding board” for all judges, someone who “will listen and raise questions, but without dictating answers.”

In 2013, Supreme Court Chief Justice John G. Roberts appointed Collyer to the FISC. In 2016, she reduced her caseload by going to “senior status” when Roberts named her FISC’s presiding judge. Among her last actions on the FISC was a rare reprimand of the FBI regarding its handling of applications for warrants to surveil Page.

In 2017, Collyer was diagnosed with ovarian cancer. She continued to carry a full caseload through treatment and, a year later, doctors declared she was free of the cancer. She soon developed a related but rare neurological disorder that forced her to step down from the bench in March 2020.

In recent years, Collyer renewed her connection with two law school classmates, Debra Lappin and Kris Hoeltgen. In March, the three launched a scholarship fund for the University of Denver Sturm Collee of Law to provide scholarships for women students. She also worked on her memoir, which is scheduled to be published by University Press of Kansas in spring 2027.

Besides her husband, Collyer is survived by her son, Timothy Collyer (Sarah) and grandchildren Eleanor Devona Collyer and Finnegan Pratt Collyer of St. Charles, Ill.; brother Paul Mayers (Mary) of Hilton Head, S. Car.; and sisters Eileen Zebroski of Ponte Vedra Beach, Fla., Ruth Schofield (Bart) of  Wolcott, Conn., and Brenda Danielson of Seal Beach, Cal.