Monrovia, CA has a population of 37,090 and is the 1,122nd largest city in the United States. The population density is 2,726 per sq mi which is 1073% higher than the California average and 2909% higher than the national average. The median age in Monrovia is 39 which is approximately 9% higher than the California average of 36. In Monrovia, 53% of the population over 15 years of age are married, 60% speak English and 26% speak Spanish. 59% of Monrovia residents were born in California, 16% were born out of state, 1% were born outside of the United States and 25% were foreign born.