Billerica is a town located in the U.S. state of Massachusetts. It is within Middlesex County and named after the town of Billericay in Essex, England part of the Boston-Cambridge-Newton Metro Area. It has a total area of 26.4 square miles at 42°33′30″N 71°16′10″W. The elevation is 250 feet above sea level. As of the 2010 census data, it had a total population of 40,243. The population density was 1,500/sq mi. Estimated per capita income in 2016 was $37,468. Recent job growth is positively increased by 1.74 percent. The average travel time is 17 minutes. It has Zip codes 01821 and 01862.