Port Loko District is a district in the North West Province of Sierra Leone. It is the most populous District in the North and the second most populous District in Sierra Leone, after the Western Area Urban District. As of the 2015 census, Port Loko District has a population of 614,063. The district capital is the town of Port Loko and its largest city is Lunsar. The other major towns in the district include Masiaka, Rokupr, Pepel, Lungi and Gbinti.
The district of Port Loko borders the Western Area to the west, Kambia District to the north, Bombali District to the east and Tonkolili District to the south. The district occupies a total area of 5,719 km² and comprises eleven chiefdoms. The population of Port Loko District is predominantly Muslim and the Temne people form by far the largest ethnic group in the district.