Tentative no more: Los Angeles County officially has more than 10 million residents, making it the single most populous county in the US, reportsKPCC, citing new data from the US Census Bureau. The State Board of Finance speculated late last year that LA County had passed the ten-mill mark in 2013, but the just-released Census data for 2012 and 2013 confirms the numbers. Perspective: 10 million people means that the county has more residents than 43 states and is three times more populous than the second largest county in the state (San Diego). What helped LA swell? People are just coming in from all sides: while native residents were popping out slightly more babies than before, LA County was experiencing the US’s largest increase in international migrants (migrants here includes the foreign-born, as well as US soldiers returning from overseas and ex-pats who have decided to re-pat.) Los Angeles itself saw the US’s third-largest population increase, gaining more than 65,000 new residents.