 A 2003 study, released once every 10 years, listed Benton County (of which Corvallis makes up the majority of the population) as the least religious county per capita in the United States.Only one in four people indicated that they were affiliated with one of the 149 religious groups the study identified.The study indicated that some of the disparity, however, may be attributed to the popularity of less common religions (ones not included as an option in the study) in the Pacific Northwest.