Simplify the following text for a Grade 7 native English-speaking person.
Original: Iowa is bordered by the Mississippi River on the east ; the Missouri River and the Big Sioux River on the west ; the northern boundary is a line along 43 degrees , 30 minutes north latitude .
Simplified: The western border is marked by the Missouri and Big Sioux rivers . The northern border is a line 43 degrees , 30 minutes north latitude .