The League of American Bicyclists has rated Colorado as the sixth most bicycle-friendly state in the nation for the year 2014. This is due in large part to Front Range cities like Boulder, Fort Collins and Denver placing an emphasis on legislation, programs and infrastructure developments that promote cycling as a mode of transportation. Walk score has rated Denver as the third most bicycle-friendly large city in the United States. According to data from the 2011 American Community Survey, Denver ranks 6th among US cities with populations over 400,000 in terms of the percentage of workers who commute by bicycle at 2.2% of commuters. B-Cycle – Denver's citywide bicycle sharing program – was the largest in the United States at the time of its launch, boasting 400 bicycles. Through the acquisition of new grants, the program has expanded each year, adding dozens of new stations, hundreds of bikes, and by beginning service during the winter months.
Denver is in the center of the Front Range Urban Corridor, between the Rocky Mountains to the west and the High Plains to the east. Denver's topography consists of plains in the city center with hilly areas to the north, west and south. According to the United States Census Bureau the city has a total area of 155 square miles (401 km2), of which 153 square miles (396 km2) is land and 1.6 square miles (4.1 km2) (1.1%) is water. The City and County of Denver is surrounded by only three other counties: Adams County to the north and east, Arapahoe County to the south and east, and Jefferson County to the west.