High Quality Content by WIKIPEDIA articles! Colfax Avenue is the main street that runs east and west through the Denver-Aurora metropolitan area in Colorado. As U.S. Highway 40, it was one of two principal highways serving Denver before the Interstate Highway System was constructed. In the local street system, it lies 15 blocks north of the zero point (Ellsworth Avenue, one block south of 1st Avenue). For that reason it would normally be known as "15th Avenue". However, the street was named for the 19th-century politician Schuyler Colfax, as was the town of Colfax, California. On the east it passes through the city of Aurora, then Denver, and on the west, through Lakewood and the southern part of Golden. Colfax Avenue cuts through Original Aurora, the city's historic core, and skirts the southern edge of downtown Denver. Because of the dense, mixed-use character of the development along Colfax Avenue, the Regional Transportation District bus route 15 - East Colfax has the highestridership in the RTD system.