I-70 in Kansas contains the first segment in the country to start being paved and to be completed in the Interstate Highway System.

At Colby, I-70 begins to turn southeast until it reaches Oakley, where US 40 joins with I-70 for a concurrent journey through most of the state.

From Bonner Springs to 18th Street and extending on to the Kansas eastern border, the highway is free.

I-70 enters Missouri via a main northern route on the Lewis and Clark Viaduct above the confluence of the Kansas River and Missouri River and a route designated "Alternate I-70" which has signs for I-70 as well as I-670 just south of Kansas City main downtown area.

From exit 275 at Abilene to the Missouri state line, the road is named the Dwight D. Eisenhower–Harry S. Truman Presidential Highway.

It retains the designation until exit 16 in Missouri at Independence, the location of Truman's presidential library.