WASHINGTON — Interior Secretary Ken Salazar will step down from his cabinet position in the Obama administration and return to Colorado to spend time with his family, his office has confirmed to The Denver Post.

Salazar is expected to broadly announce his departure Wednesday. He has told President Barack Obama that he intends to leave his job by the end of March.

Salazar, 57, will have served a little more than four years in Obama’s cabinet after being plucked from his beloved U.S. Senate seat serving Colorado in 2008.

His decision on whether to stay on at the helm of Interior or return to Colorado — and likely the less-glamorous but more-lucrative private sector — has been weighing on Salazar for a long time.

The president and the vice president have indicated they would like him to stay on at Interior.

“I want to thank Ken for his hard work and leadership on behalf of the American people,” President Barack Obama said Wednesday. “As the Secretary of the Interior, Ken has helped usher in a new era of conservation for our nation’s land, water, and wildlife. Ken has played an integral role in my Administration’s successful efforts to expand responsible development of our nation’s domestic energy resources. In his work to promote renewable energy projects on our public lands and increase the development of oil and gas production, Ken has ensured that the Department’s decisions are driven by the best science and promote the highest safety standards. Ken has also made historic strides in strengthening our nation to nation relationship with Indian Country, helping to resolve longstanding disputes and make tribal communities safer and stronger. I have valued Ken’s friendship since we both entered the Senate in 2005, and I look forward to receiving his counsel even after he returns to his home state of Colorado.”

Obama, at a campaign event in Pueblo last year, called Salazar “one of the finest senators that the state of Colorado ever had, who is now doing a great job looking after the natural resources of this beautiful country of ours.”

Last fall, Salazar spent much his personal time campaigning for Obama in Colorado. When badgered about his future by local and national reporters, he usually demurred, saying he wanted to get the president re-elected before thinking about it.

The secretary is not shy talking about how much he loves his job as steward of the country’s public lands. He often says the Department of Interior is really the Department of America.

“As I think about my role as secretary of the Interior, it is perhaps the most wonderful job of any cabinet position in the United States,” Salazar said in December. “I would not trade it for attorney general or Housing and Urban Development or Transportation because I would find those jobs a little boring.”

But the pull of family obligations — he and his wife are primary caretakers of their 5-year-old granddaughter who has autism and is enrolled in a special school — was too great to commit to four more years, Salazar’s office said.

His days in Washington are long. Some weeks he spends 16 hours a day traveling from one far-flung location to the other — from some pristine causeway in California to the Hurricane Sandy-ravaged New Jersey coast.

Salazar has said in his four years he is most proud of improving the relationship the federal government has with American Indians, cleaning up the oil and gas program after former departments were plagued with scandal and nepotism, and broadening a clean energy agenda.

The secretary established seven new national parks and 10 new wildlife refuges. He also launched 18 utility-scale solar energy projects on public lands. Before 2009, there were hundreds of pending applications but no construction projects approved.

He has also dealt with several natural and environmental disasters, including the explosion of a BP-operated deep water oil well, Deepwater Horizon, in the Gulf of Mexico in April 2010.

Roughly 53,000 gallons of crude poured into the sea a day for nearly three months. While weathering criticism, Salazar issued a moratorium on new offshore drilling leases and launched an aggressive overhaul of safety standards for offshore oil and gas development.

In his push to grow regulations for domestic energy production on federal lands — particularly post Deepwater Horizon — he often tangled with House Republicans, many of whom have called him one of the worst Interior secretaries in the history of the United States.

Salazar usually fired back. In an April 2012 speech at the National Press Club, he called House Republicans “charter members of the Flat Earth Society” who lived in an imaginary energy world of “fairy tales.”

“It’s a place where up is seen as down, where left is seen as right, where oil shale seems to be mistaken every day in the U.S. House of Representative for shale oil, where record profits justify billions of dollars in subsidies,” he said.

Salazar’s future in politics — at least in Colorado — is unclear.

Many old Democratic hands would love to see him seek statewide office again, though the high-profile seats are tied up with other Democrats, Gov. John Hickenlooper and Sens. Mark Udall and Michael Bennet.

Should Hickenlooper decide to run for — and win — a second term, he would be governor until 2018. Udall has already announced his 2014 re-election campaign and Bennet doesn’t have to run again until 2016.

Allison Sherry: 202-662-8907, asherry@denverpost.com or twitter.com/allisonsherry

About Ken Salazar

Home: Alamosa

Education: Colorado College, political science, 1977; University of Michigan Law School, 1981

Career highlights

Named chief legal counsel to Gov. Roy Romer, 1986Appointed director of Colorado Department of Natural Resources, 1990

Elected Colorado Attorney General, 1998

Re-elected in 2002

Elected to U.S. Senate, 2004

Tapped by President Barack Obama as secretary of the Interior, 2009