Looking for a reliable oil and gas provider? We've featured 10 top oil and gas companies in Iowa below! 1. Diamond Oil Co. Local to the state of Iowa, Diamond Oil Co. operates out of multiple locations statewide, including Ames, Lincoln, and Perry. The company was founded by John Chance and Dick Rice back in 1978, developing a reputation for reliability and quality … [Read more...] about 10 Top Oil and Gas Companies in Iowa