It runs in a north south direction
I-35 is the primary north to south interstate highway in Iowa.
The major highways in the state of Iowa are Interstate 35 and Interstate 29. They join the north and south part of the state. Interstate 80 and Interstate 380 join the east and west side of the state.
Interstate 40, Interstate 75, Interstate 65, Interstate 81, Interstate 55...
I-35 is the primary north to south interstate highway in Iowa. It enters Iowa from the Minnesota state line at Council Bluffs, Iowa and runs south to the Missouri state line at Lamoni, Iowa.
22 runs in an east-west direction. Odd numbered ones run N-S, even run E-W (generally)
The US Interstate Highway that runs through Helena, Montana is Interstate 15.
Interstate 10
65
Interstate 37.
Interstate 80 travels in an east-west direction across the state of Wyoming.
Interstate 65 will take you from Mobile Alabama to Birmingham Alabama.
Interstate 90 :0