When Air Force One touches down in South Dakota on Friday, President Barack Obama will mark a milestone: He'll have visited all of America's 50 states while in office.
Obama joins just three other presidents thus far -- Bill Clinton, George H.W. Bush and Richard Nixon -- to complete the task of visiting each of the states during their time as commander-in-chief.
Obama is making a quick stop in South Dakota to give the commencement address at Lake Area Technical Institute's graduation ceremony in Watertown.
Pete Souza, the chief official White House photographer, has accompanied Obama to document his visits, and has posted a gallery on Medium of stops in each state to lead up to the big 50 marker.
The gallery also includes one of Obama giving Vice President Joe Biden some epic side-eye.
One South Dakota resident in particular is sure to be pleased that the president visited; 11-year-old Rebecca sent a letter to Obama in April, describing the best her state had to offer.
"We are the warmest of the Dakotas... and when I just go to the park, I sometimes see coyotes, hawks, and bald eagles," she wrote.
Rebecca's heart can officially mend when President Obama visits South Dakota tomorrow → http://t.co/Cm9KnTEfDR pic.twitter.com/FNsposqhaT— The White House (@WhiteHouse) May 7, 2015
At the start of the year, Obama had visited 46 states. The four remaining -- Idaho, South Carolina, Utah and South Dakota -- are reliably Republican states.
Obama did visit South Dakota in 2008 while campaigning for his first term in office, and spoke in North Dakota last year at the Standing Rock Indian Reservation that straddles South Dakota.
Some information from the Associated Press.