Nikiski, AK has a population of 5,029 and is the 6,450th largest city in the United States. The population density is 72 per sq mi which is 6485% higher than the Alaska average and 20% lower than the national average. The median age in Nikiski is 44 which is approximately 32% higher than the Alaska average of 34. In Nikiski, 50% of the population over 15 years of age are married, 91% speak English and 5% speak Spanish. 39% of Nikiski residents were born in Alaska, 58% were born out of state, 1% were born outside of the United States and 2% were foreign born.