• n'djam?na, formerly known as fort-lamy, is the capital of chad and its largest city. population: 594,000 (1988). n'djam?na, formerly known as fort-lamy, is the capital of chad and its largest city. population: 594,000 (1988). n'djam?na, formerly known as fort-lamy, is the capital of chad and its largest city. population: 594,000 (1988).