Sampson Flat is in eastern Fresno County about eight miles north of Dunlap and 45 miles east of Fresno. The district includes the area known as Davis Flat. Sometimes it has been included in the Mill Creek District. It was placer-mined in the early days, and the lode mines were active from the 1880s until about 1915.
The district is underlain by granodiorite, gabbro and small amounts of pyroxenite. Several northtrending quartz veins two to three feet thick contain free gold and varying amounts of sulfides. There is some tungsten mineralization in bodies of tactite.
Davis Flat, Delilah (Black Jack & Hercules), Little Monitor, Oro Fino, Sampson.
Bradley, Walter W., 1916, Fresno County, Delilah Mining Co. California Min. Bur. Rept. 14, p. 443.