There are 63 counties in Louisiana. The most populous county in the state of Louisiana, with a population of 440,956, is East Baton Rouge Parish. Since the last U.S. census was taken in 2010, East Baton Rouge Parish has seen a population growth of just 0.09%. Other major counties in Louisiana following East Baton Rouge Parish are Jefferson Parish (434,051), Orleans Parish (391,006) with the city of New Orleans, St. Tammany Parish (258,111), Caddo Parish (242,922) with the city of Shreveport, and Lafayette Parish (242,782) with the city of Lafayette. Of these counties, only Caddo Parish reported a declining population with a growth rate of -4.96%. Orleans Parish experienced the most rapid growth at 12.43%.
The least populous county in the state of Louisiana, with a population of 4,462, is Tensas Parish. Tensas Parish has seen a decrease in its population since the census with a growth rate of -14.7% since the 2010 census. Louisiana has many other parishes with populations below 10,000 including Cameron Parish (6,968), East Carroll Parish (7,037), Red River Parish (8,477), Catahoula Parish (9,608), and Caldwell Parish (9,960). All of these parishes have experienced a decline in population except Cameron Parish which has grown 0.75%. Tensas Parish had the most significant population decline.
The parish with the most rapid rate of growth in Louisiana is St. Bernard Parish. Since 2010, St. Bernard Parish has seen an impressive growth rate of 26.88%, bringing the population in 2019 up to 46,721. Behind St. Bernard Parish is Ascension Parish (15.56%), Orleans Parish (12.43%), and West Baton Rouge Parish (10.32%). Tensas Parish has seen the most rapid decrease in population with a growth rate of -14.7% since 2010.