KIACHTI, or KIACHTA, a town of Siberia, government of Irkutsk, on the Kiashta, a small affluent of the Selenga, 180 miles S.E. of Irkutsk. Kiachti is situated close to the Chinese frontier, and is the great emporium of trade between Russia and China. It consists of an upper and lower town; the former contains the public offices, barracks, &c. — the latter, about 2 miles farther S., is inhabited chiefly by merchants. On the Chinese side, and within a mile of the lower town, is the Chinese village of Mai-Maitchin with which the chief traffic of Kiachti is carried on. A great fair is held annually between the two places in December. The Russians exchange furs, leather, broad cloths, coarse linens, bullion, glass, cattle, &c., for tea, manufactured silks and cottons, china-ware, rhubarb, toys, and other Chinese produce. In 1843 the Russians imported through Kiachti, 102,700 chests of tea; and the value of woollen and cotton goods, leather and furs, received by the Chinese merchants in that year amounted to above 1,677,200. This, however, is about double the amount of trade in ordinary years — the great increase being occasioned by the English war with China. Pop. about 5000.