Ashtabula, OH has a population of 18,540 and is the 2,355th largest city in the United States. The population density is 2,385 per sq mi which is 826% higher than the Ohio average and 2533% higher than the national average. The median age in Ashtabula is 39 which is approximately 1% lower than the Ohio average of 39. In Ashtabula, 47% of the population over 15 years of age are married, 93% speak English and 5% speak Spanish. 78% of Ashtabula residents were born in Ohio, 17% were born out of state, 2% were born outside of the United States and 2% were foreign born.