Located between the Lúčanská Malá Fatra and Martinské hole Hills at the valley of the Rajčanka river, the spa is marked as Thermae on a map from 1376, but a deed by Luis the Great gives the first written account of the hot water springs named Villa Tapolcha.

In the donation deed made by the king Vladislaus II for Štefan Zápoľský from 1496, the spa is referred to as "possessio Thoplycza", what could mean a settlement or a hamlet.

The new prime time of the spa came only by the end of the 18th century, when baron Ján Kalis, one of the heirs of the Lietava domain, built a brick house with 14 rooms at significant costs.

In 1793, Dr. Amadé Kelin, a physician of the Turčianska County, published in Vienna the first monograph about Rajecké Teplice, promoting the spa town throughout Hungary.

The 19th century saw a comprehensive development of spa facilities, with spas becoming a popular summer residence for gentry, high aristocracy and wealthy bourgeoisie.