Fort Irwin, CA has a population of 9,337 and is the 4,143rd largest city in the United States. The population density is 1,340 per sq mi which is 477% higher than the California average and 1380% higher than the national average. The median age in Fort Irwin is 22 which is approximately 39% lower than the California average of 36. In Fort Irwin, 68% of the population over 15 years of age are married, 79% speak English and 11% speak Spanish. 22% of Fort Irwin residents were born in California, 64% were born out of state, 4% were born outside of the United States and 10% were foreign born.