 The first Colorado portion of I-70 opened to traffic in 1961. This section bypassed and linked Idaho Springs to the junction where US 6 currently separates from I-70 west of the city. The majority of the alignment through Denver was completed by 1964. The Mousetrap reused some structures that were built in 1951, before the formation of the Interstate Highway system. The last piece east of Denver opened to traffic in 1977.
