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.
The city is situated in the southeast section of the state in the Arkansas Delta with the Arkansas Timberlands region to its immediate west. Its topography is flat with wide expanses of farmland consistent with other places in the Delta Lowlands. Pine Bluff is home to a number of creeks, streams, bayous (Bayou Bartholomew is the longest bayou in the world and is the second most diverse stream in the United States), and larger bodies of water such as Lake Pine Bluff, Lake Langhofer (Slack Water Harbor) and the Arkansas River.