Estelline Community Oil Co. was started in 1930 by farmers, ranchers, and the towns people of the Estelline area; looking for services that would help out the community and boost the local economy without traveling too far to a larger town. In 1977, the co-op invested in adding the Castlewood station to better serve the needs of the people in the Castlewood area. The Station located on 201 4th St N. in Estelline was re-built in June of 1997 and has been prospering since.
With the co-op's business growing they decided to convert the old tire warehouse outside of town, on State Avenue, to the Agronomy and Seed warehouse. For years after the move outside of town the business for Agronomy and Seed began to take off. With business growing and limited space becoming a problem, the co-op knew something needed to be done. In 2010, Estelline Community Oil invested in separating the two departments and built a new seed warehouse.