From the Super Mario Wiki
A family driving through Kansas

Kansas is one of the fifty states of the United States of America.

In The Adventures of Super Mario Bros. 3 episode of "Mush-Rumors", a Wichitan family of four are driving through Kansas on their way to Wild Waldo's One-of-a-Kind Amusement Park. They drive into what they think is a tunnel but is actually a Warp Zone that leads to the Mushroom Kingdom. When they exit the Warp Zone they question if they are in Iowa or Nebraska. Everyone in the Mushroom Kingdom is spreading a rumor that the family are aliens. After Mario and Luigi find the family, they help them get back to the real world.

In the Nintendo Adventure Book Leaping Lizards it is stated that Luigi once saved Topeka, Kansas from a flood caused by a clog. During a picnic, Mario lies to Princess Toadstool and states that he was the one who fixed the clog.