Port Byron, IL has a population of 1,670 and is the 12,080th largest city in the United States. The population density is 674 per sq mi which is 203% higher than the Illinois average and 644% higher than the national average. The median age in Port Byron is 45 which is approximately 20% higher than the Illinois average of 37. In Port Byron, 69% of the population over 15 years of age are married, 97% speak English and 2% speak Spanish. 61% of Port Byron residents were born in Illinois, 37% were born out of state, 0% were born outside of the United States and 2% were foreign born.