Packaging Corporation of America (PCA) is a producer of containerboard and corrugated products in the United States. The Company is consisted of mills and corrugated manufacturing operations. The mill operations consists of two kraft linerboard mills located in Counce, Tennessee, and Valdosta, Georgia, and two medium mills located in Filer City, Michigan, and Tomahawk, Wisconsin. The Mills transfer the majority of their containerboard produced to PCA’s corrugated products plants. PCA’s corrugated manufacturing operations consist of 71 plants, with 41 operating as combining operations, or corrugated plants, and 30 as sheet plants; a technical and development center, six graphic design centers and a complement of packaging supplies and distribution centers. On April 14, 2011, the Company acquired Field Packaging Group. On September 10, 2011, the Company acquired Packaging Materials Company. On November 30, 2011, PCA acquired Colorado Container.