Blawenburg, NJ has a population of 305 and is the 22,410th largest city in the United States. The population density is 502 per sq mi which is 50050% higher than the New Jersey average and 454% higher than the national average. The median age in Blawenburg is 42 which is approximately 6% higher than the New Jersey average of 40. In Blawenburg, 80% of the population over 15 years of age are married, 67% speak English and 0% speak Spanish. 46% of Blawenburg residents were born in New Jersey, 34% were born out of state, 0% were born outside of the United States and 20% were foreign born.