In 1945, the Winter Sports Committee of Denver sent Laurence "Larry" Jump and Frederick "Sandy" Schauffler out to locate a potential ski area in the Front Range of Colorado. After surveying land, a site was discovered on the western side of Loveland Pass. The duo hired Richard Durrance to join in the development of the new ski area. Initial estimates for the construction of the area ranged at about $150,000. This included two lifts, a rope tow and trails. An application was submitted to the Forest Service the following year. After approval, forest ranger Wilfred David, designed the trail system.
Later that year, the developers of Arapahoe Basin met a local resident Max Dercum. Dercum came from Pennsylvania where he was a professor of forestry. This background became useful with the construction of the area. The ski area opened for the 1946-47 season with solely a tow, which ran from mid-mountain to the summit. Skiers were then transported to the tow location using four wheel drive vehicles. Tickets that season ran at three dollars per day.For the 1947-48 season, a single chair was installed, which used metal parts. This was rare for this time period, as World War II was just ending. According to the area, the lift was the first metal chair installed in post-war times. The area was powered by a 100 kilowatt generator. Skier visits topped more than 13,000 people, a huge increase over the previous year.When Sandy Schauffler decided to leave the area in 1949, the operations were left to Larry. He ran the area until the mid-1960's when Joe Jankovsky, a patrolman, took over. Joe managed the ski resort until he purchased it in 1972 for $850,000. Big changes took place at Arapahoe Basin when Ralston-Purina bought the area in 1978. The lift company, Lift Engineering (Yan), installed one triple chair and three doubles. This eliminated all surface lifts and single chairs. Skier numbers increased to 250,000 people per season by this time.
Ownership stayed with Ralcorp for the next two decades until Vail Resorts announced their plans to purchase the ski operations from them. Ralcorp's Summit County areas consisted of Keystone, Breckenridge and Arapahoe Basin. In 1997, the Department of Justice ruled that the ownership of Keystone, Breckenridge, Arapahoe Basin, Vail, and Beaver Creek controls the ski market in the Summit County area. Vail Resorts then decided to sell Arapahoe Basin to Dundee Realty Corporation of Canada.
Improvements to A-Basin began after Dundee took control of the ski area. In 2001, Poma replaced the old Lenewee lift with a new triple chair. Following the lift install, the ski area won approval to install a snow making system. This allowed A-Basin to compete with Loveland to be the first ski area to open, typically in mid October. Their new system covers three trails, two off of Exhibition and another on Lenewee.
During the summer of 2005, the area constructed a new equipment rental facility. This building was the first new addition to the base area in many years. Also that year, Arapahoe Basin actively sought approval for their Montezuma Bowl expansion. This incorporated a new lift on the backside of the mountain and various intermediate and expert trails. The Forest Service approved their request in 2006.A new mid mountain lodge opened at the summit of the Exhibition lift during March of 2007. The lodge increases the ski area's cafeteria seating capacity by about three hundred. During July of 2007, construction on the new Zuma Quad built by Leitner-Poma began. The new lift opened during January of 2008.