High Quality Content by WIKIPEDIA articles! Interstate 70 (I-70) is a mainline route of the Interstate Highway System in the United States connecting Utah and Maryland. The Utah section runs east–west for 232.15 miles (373.61 km) across the central part of the state. Richfield is the largest Utah city served by the freeway, which does not serve or connect any urban areas in the state. The freeway was built as part of a system of highways connecting Los Angeles and the northeastern United States. I-70 was the second attempt to connect southern California to the east coast of the United States via central Utah, the first being a failed attempt to construct a transcontinental railroad. Parts of that effort were re-used in the laying out of the route of I-70.