In 1727, the Burinsky Treaty was signed between the Russian Empire and the Qing Empire, establishing the border between the two states. That same year, the city of Kyakhta was founded on the border of Russia and China by the order of Russian diplomat Savva Raguzinsky-Vladislavich.

Due to its strategic location, the city became a center of trade. To protect against potential attacks from nomadic tribes, the Troitskosavsk fortress was built. Inside the fortress, a church was erected with an altar dedicated to Saint Savva of Serbia, the heavenly patron of Savva Raguzinsky-Vladislavich. Nearby, a trading settlement emerged with small squares, workshops, inns, and warehouses. Soldiers and Cossacks from the surrounding areas were recruited for construction: 350 soldiers from the Yakut regiment and 30 Cossacks from Verkhneudinsk, as well as workers from the Ilim and Kabansk fortresses. The settlement featured six Mongolian yurts and a large courtyard with twelve barns for storing supplies. The fortress was quadrilateral, with each side measuring 213 meters. Watchtowers stood at the corners and by the gates. Inside, more than 30 houses for merchants were built, along with a guest house containing 24 shops and 24 barns. The construction of the Kyakhta settlement was completed in 1728, and it became the center of Russian-Chinese trade.

Through Kyakhta, leather, fabrics, furs, and manufactured goods were sent to China, while tea, porcelain, paper, and silk fabrics were brought back from China. For a long time, almost all tea exports from China to Russia and Europe passed through Kyakhta, and in Russia, tea was referred to as "Kyakhta tea."

In 1774, the first administrative buildings appeared in the settlement, and in 1792, the state customs office was moved from Irkutsk to Kyakhta. In 1796, construction began on a wheeled postal road from Irkutsk to Kyakhta, later named the Circum-Baikal Road. It extended to the southern tip of Baikal and turned towards Mongolia but was inconvenient for merchants. Therefore, it was decided to build a road along the southern shore of Baikal, which was completed by 1869 and became the basis for the future Circum-Baikal Railway.

By 1750, a new wooden church dedicated to the Resurrection of Christ, with altars for the Assumption of the Holy Mother of God and Saint Nicholas the Wonderworker, was built and consecrated in Kyakhta.

In 1805, Troitskosavsk received city status, and by 1829, its population exceeded 4,000 people.

On May 22, 1868, a fire occurred in Kyakhta, destroying a large part of the city, including archives dating back to 1801.

From the mid-19th century, Kyakhta became the "business capital" of the eastern part of the Russian Empire. To develop market relations, the Alexeyev Real School was opened, becoming an example of public education. In 1811, a parish county school opened in Troitskosavsk. In the 1840s, playing the piano became popular among wealthy families in Kyakhta. The city had its own choir and theater, where plays by Ostrovsky, Potehina, and Sumbatov-Yuzhin were staged. In 1873, the first meteorological station in Transbaikalia was opened in Troitskosavsk.

In 1880, Kyakhta entrepreneurs established the "Kyakhta Steamship Company," which later purchased the assets of the "Baikal Shipping Company" and organized postal and passenger transport across Baikal. In 1885, a saltworks opened at Lake Kiran. Profits from trade were invested in gold mining, shipping, industry, and charity.

In the 19th century, Troitskosavsk was a wealthy merchant city, known as the Sandy Venice and Zabaluik town. However, after the opening of the Suez Canal in the late 19th century, most imports from China began to arrive by sea, and the significance of Kyakhta's trade diminished. The opening of the Chinese Eastern Railway in 1903 finally deprived Kyakhta of its status as the main trading point between Russia and China.

Over the years of Russian-Chinese trade, a unique dialect formed in this area, a mix of Russian and Chinese languages, known as the "Kyakhta dialect." The main vocabulary was Russian, but Chinese grammatical forms and verbs were often used.

Kyakhta became a transit point for travelers and pioneers. Expeditions by Przhevalsky, Potanins, Obruchevs, Kozlov, and others passed through it, leaving notes in their diaries.

On May 25, 1915, the Kyakhta Treaty was signed in the city between Russia, Mongolia, and China, determining Mongolia's international status. Later, a camp for prisoners of war was established here, housing up to 6,700 people.

Today, Kyakhta is a city of district significance in the Republic of Buryatia. It hosts museums and exhibitions, the main one being the Kyakhta Local History Museum named after V. A. Obruchev.