Gridley, CA has a population of 6,558 and is the 5,427th largest city in the United States. The population density is 3,147 per sq mi which is 1254% higher than the California average and 3374% higher than the national average. The median age in Gridley is 32 which is approximately 10% lower than the California average of 36. In Gridley, 56% of the population over 15 years of age are married, 58% speak English and 39% speak Spanish. 67% of Gridley residents were born in California, 8% were born out of state, 1% were born outside of the United States and 23% were foreign born.