Saint Croix is an island in the Caribbean Sea, and a county and constituent district of the United States Virgin Islands (USVI), an unincorporated territory of the United States.
St. Croix is the largest of the islands in the territory, being 28 by 7 miles (45 by 11 km). However, the territory's capital, Charlotte Amalie, is located on Saint Thomas.
The island was inhabited by various indigenous groups during prehistory. Christopher Columbus landed forces on the island on November 14, 1493 and was attacked by the Kalinago, who lived at Salt River on the north shore. Control of the island was traded among various powers, including Spain, Netherlands, Knights of Malta, and Great Britain before it became a possession of France from 1650 until 1733. On June 13, 1733, France sold the island group to the Danish West India Company. For nearly 200 years, St. Croix, St. Thomas and St. John were known as the Danish West Indies; around the mid to late eighteenth century, «at the peak of the plantation economy, the enslaved population of St. Croix numbered between 18,000 and 20,000, the white population ranging between 1,500 and 2,000».
In 1916, Denmark sold St. Croix, St. Thomas and St. John to the United States, formalizing it in the Treaty of the Danish West Indies, in exchange for a sum of US$25 million in gold. In a national referendum on the issue, 64.2% of Danish voters approved the sale. An unofficial referendum held in the islands resulted in 99.83% vote in favor of the purchase. The island's inhabitants were granted United States citizenship in 1927. Industrialization of the island and its move away from an agrarian society took place in the 1960s. The 2012 shutdown of the Hovensa refinery resulted in the loss of many jobs, so that some people have returned to subsistence agriculture.