1956
June 29 - President Eisenhower signed the Federal Aid Highway Act. It provided a 90 percent federal share of costs for constructing a 41,000-mile Interstate network.

October 21 - The Kansas Turnpike was opened for a toll-free day and official opening ceremonies.
Read more about the Kansas Turnpike

November 14 - Kansas opened the first section of interstate in the nation just west of Topeka.
Read more about I-70

November 29 - The section of Route 1 from Russell directly east to Salina was substituted for the section of Route 1 from Russell via Ellsworth to Salina.

1957
August 14 - the "Official Route Numbering for the Main Routes of the National System of Interstate and Defense Highways" was adopted by the American Association of State Highway Officials. (This did not include I-35W.)

1958
April 22 - Kansas set a record with the first Interstate connection across a state line – into Missouri.

1959
October 9 - A 20-mile stretch of I-70 between Junction City and Abilene was opened.