The following outline is provided as an overview of and topical guide to Tajikistan: Tajikistan – mountainous, landlocked, sovereign country located in Central Asia. Tajikistan borders Afghanistan to the south, Uzbekistan to the west, Kyrgyzstan to the north, and China to the east. Most of Tajikistan's population belongs to the Tajik ethnic group, who share culture and history with the Persian peoples and speak the Tajik language, a modern variety of Persian. Once part of the Samanid Empire, Tajikistan became a constituent republic of the Soviet Union in the 20th century, known as the Tajik Soviet Socialist Republic (Tajik SSR).