SC 42 may refer to:
Siemens SC-42, a model of the Siemens Charger locomotive. Convoy SC 42, a World War II transatlantic convoy of merchant ships , a United States Navy submarine chaser commissioned in 1918 and sold in 1921 Scandium-42 (Sc-42 or 42Sc), an isotope of scandium South Carolina Highway 42 (1920s), a former state highway from Sumter to Bishopville South Carolina Highway 42 (1930s–1940s), a former state highway from northeast of Cope to Orangeburg