President Obama on Friday became just the fourth commander in chief to visit all 50 states during his time in office, finally traveling to South Dakota.

"It's good to be in South Dakota," he said, delivering the commencement address at a community college in Watertown. "I am thrilled to be here … I was saving the best for last."

As a presidential candidate in 2008, then-Sen. Obama visited Mount Rushmore. He quipped at the time, "I don't think my ears would fit."

Presidents Richard Nixon, George H.W. Bush and Bill Clinton also traveled to all 50 states during their tenures.

Obama recently visited Idaho and South Carolina, among other red-leaning states, in his quest to visit all 50 states.

There's a reason South Dakota wasn't high on the president's list of places to travel. He lost the Democratic primary there to Hillary Clinton in 2008 and was drubbed in South Dakota in the general election in both 2008 and 2012.

Obama's next challenge? Visiting all the U.S. territories.

The White House had no comment on whether Obama would take on that task.