Frankfurt, officially known as Frankfurt am Main, is the largest city in the German state of Hessen and the fifth-largest city in Germany, with a population of 701,350 (2013) within its administrative boundaries.[4] The actual urban area (Frankfurt Rhein-Main) has a population of 2,221,910. The city is at the centre of the larger Frankfurt Rhine-Main Metropolitan Region which has a population of 5,500,000[1] and is Germany's second-largest metropolitan region. Since the enlargement of the European Union in 2013, the geographic centre of the EU is about 40 km (25 mi) east of Frankfurt.