20th century. The decline was uneven, however: the population in the largest cities – Marquette, Sault Ste Marie, and Escanaba – grew somewhat, while smaller cities and non-urban areas have generally declined in population. The six westernmost counties experienced the largest decrease, from a 1920 population of 153,674 to a 2020 population of 79,392. Many ghost towns exist in the region. A "" indicates an increase in population from the previous census, and a "" indicates a decrease in population from the previous census. Economy Industries The Upper Peninsula is rich in mineral deposits, including iron, copper, nickel, and silver. Small amounts of gold have also been discovered and mined. In the 19th century, mining dominated the economy, and the UP became home to many isolated company towns. For many years, mines in the Keweenaw Peninsula were the world's largest producers of copper (see Copper mining in Michigan). The mines began declining as early as 1913, with most closing temporarily during the Great Depression. Mines reopened during World War II, but almost all quickly closed after the war ended. The last copper mine in the Copper Country was the White Pine mine, which closed in 1995. Marquette County sits along the Marquette Iron Range, which sent out a significant portion of the iron ore mined in the United States for many years. , Marquette County is home to one remaining iron ore mine and one nickel and copper mine. From approximately 1870 to 1915, about 32 quarries mined Jacobsville Sandstone in the Upper Peninsula, particularly near Marquette and the community of Jacobsville. The sandstone was used in many buildings, both locally and around the United States. Since logging of white pine began in the 1880s, timber has been an important industry. Stands of hemlock and hardwood in the western reaches of the forest experienced larger scale selection-cutting beginning in the mid-20th century. Because of the highly seasonal climate and the short growing season, agriculture is limited in the Upper Peninsula, though potatoes, strawberries and a few other small fruits are grown. Tourism has become the main industry in recent decades. In 2005, ShermanTravel, LLC listed the Upper Peninsula as #10 in its assessment of all travel destinations worldwide. The peninsula has extensive coastline on the Great Lakes, large tracts of state and national forests, cedar swamps, more than 150 waterfalls, and low population densities. Because of the skiing, camping, boating,