Pine Bluff is the largest city and county seat of Jefferson County, Arkansas, United States. It is also the principal city of the Pine Bluff Metropolitan Statistical Area and part of the Little Rock-North Little Rock-Pine Bluff Combined Statistical Area. The population of the city was 49,083 in the 2010 Census, however 2011 estimates show the population has since declined to 48,339. Pine Bluff is the ninth largest city in the state of Arkansas.