The California Gold Rush loosely refers to a period in the 1840s and 1850s when gold was discovered in California and tens of thousands of people flocked to the state seeking wealth. The period began in January of 1848 when James Marshall discovered gold underneath Sutter's Mill in Coloma, California, near Sacramento. (Coloma itself turned into a small town, Culloma, throughout the period, and is today a popular "ghost town" tourist attraction.) In 1849, President James Polk used the phrase "Gold Rush" to describe the movement West, which brought an estimated 200,000 to California in total. (This explains the derivation of the nickname for people to rushed in to California to earn their fortune - "Forty Niners.") By 1850, the population of the California territory was such that a governor and legislature were chosen and a Constitution drawn up. California would become a state later that year as part of the "Compromise of 1850."A variety of tours around the state of California will take visitors to historically significant sites from the Gold Rush era. Many of these are located in and around San Francisco, the US city that had the largest population boom during the Gold Rush, changing from a town of about 200 to a bustling city of 36,000 in 6 years. Some of the more notable destinations on a California Gold Rush Tour include Bodie, California, a ghost town that now serves as a state historic park, and Fourth Crossing, founded due to its proximity to rich placer ores but eventually significant as a stagecoach depot.