The Bermuda Pedestal is an oval geological feature in the northern Atlantic Ocean containing the topographic highs of the Bermuda Platform, the Plantagenet (Argus) Bank, and the Challenger Bank. The pedestal is 50 km (31 mi) long and 25 km (16 mi) wide at the 100 fathom line, while the base measures 130 km by 80 km at -4200 m. Surrounding the pedestal is a much larger mid-basin swell known as the Bermuda Rise, measuring 900 km by 600 km at the 5000 m depth contour. The islands of Bermuda are located on the southeastern margin of the Bermuda Pedestal.