Pekin, IL has a population of 34,003 and is the 1,249th largest city in the United States. The population density is 2,326 per sq mi which is 946% higher than the Illinois average and 2467% higher than the national average. The median age in Pekin is 39 which is approximately 3% higher than the Illinois average of 37. In Pekin, 57% of the population over 15 years of age are married, 98% speak English and 1% speak Spanish. 82% of Pekin residents were born in Illinois, 17% were born out of state, 0% were born outside of the United States and 1% were foreign born.