Pasadena is a city in Los Angeles County, California, United States. As of 2013, the estimated population of Pasadena was 139,731, making it the 183rd-largest city in the United States. Pasadena is the ninth-largest city in Los Angeles County. Pasadena was incorporated on June 19, 1886, becoming one of the first cities be incorporated in what is now Los Angeles County, the only one being incorporated earlier being its namesake (April 4, 1850).