Chromium is not found as the metal in nature. It's most signifacant source is Chromite (FeCr2O4), and chromite mines are found in many places, including Turkey, Russia, USA, Japan, and South Africa, which is it's biggest source. Another source is Crocoite (PbCrO4), which is found in Russia, USA, Brazil, and Tasmania. A common way to get pure chromium is the aluminothermic process, where they heat chromium oxide with charcoal or aluminum, and the charcoal or aluminum takes the oxygen and the pure chromium metal is left. Another way is converting chromite into ferrochromium, an alloy of chromium. Ferrochromium is the substance used to make stainless steel. It's added to liquid steel and dissolves, and when the steel hardens, the chromium is dissolved inside the steel, which makes stainless steel.
