(CNN) — President Joe Biden plans to declare a new national monument when he visits Colorado this week, according to people familiar with the plans, as he begins a western swing one month before the midterm elections.

The President will designate Camp Hale, a World War II training ground high in the Rocky Mountains, as a national monument during his visit Wednesday. The site was where the 10th Mountain Division trained and developed warfare techniques in the harsh, wintery conditions before heading to the Italian Alps to fight.

Making Camp Hale a national monument will protect the site from development. It has been a key priority for Colorado’s senior senator, Democrat Michael Bennet, who faces a competitive race for reelection this year.

While Biden has expanded some existing national monuments since taking office, Camp Hale will be the first one he’s created. The century-old Antiquities Act allows the President to create monuments in order to protect important areas.

Some in the state have opposed making Camp Hale a national monument, saying it could prevent future mining projects.

But Colorado Democrats have pressed the White House to take the step in order to preserve an area of environmental and historical significance.

On his trip West, Biden also plans to attend fundraisers for Democrats. He will join House Speaker Nancy Pelosi at a fundraising event Thursday on the west side of Los Angeles to boost House Democrats.

The White House said Friday that Biden would use his trip to advance his agenda and contrast it with Republicans’.

“The President will discuss the progress we have made from passing a historic Bipartisan Infrastructure Law to passing the Inflation Reduction Act. He’ll draw a contrast between his plan to protect and strengthen Medicare and Social Security, and (the) plan for congressional Republicans, which puts Medicare and Social Security on the chopping block,” White House press secretary Karine Jean-Pierre said.