This collection contains records about family members, legal cases, investments, property and ranching interests, oil interests and development in Northeastern Wyoming, and Wyoming politics.

Sackett family history is documented in some early letters from the 1880s, newspaper articles, notes, and correspondence and business dealings with his son, Carl Sackett, Jr. Most of the Sackett family estate files also contain correspondence of the respective individuals. There are various records about the Sackett Ranch and Sackett's ranching interests in the Kaycee area, including finances, land acquisition, and general operations. Of related interest are various records about the Taylor Grazing Act and its probable impact upon ranching in the region.

Sackett's personal and advisory role in oil development and exploration in Northeast Wyoming and the Kaycee Dome in particular are well-documented. Among the correspondents are oilmen L.A. Baldwin, Tom Don, C. Elliott, H.W. Hugo, and Joseph Pepper. Another prominent figure was Joseph O'Mahoney, who, as a lawyer, assisted Sackett.

Sackett's legal files contain copies of court records, notes, and in some cases, correspondence with the respective parties. Among his clients were Roy Montgomery (Gillette businessmen and politician and benefactor of the Montgomery Home for the Blind in Thermopolis) and prominent Sheridan County businessmen.