The term 'Capital South Dakota' refers to the capital city of the U.S. state of South Dakota, which is Pierre. The other three crossword solutions are the capitals of Norway (Oslo), Peru (LIMA), and Latvia (Riga). Oslo is the largest city in Norway and is located on the country's southern coast. LIMA is the capital and largest city of Peru, located in the central coastal part of the country. Riga is the capital and largest city of Latvia, located on the Baltic Sea.