It was situated between Selmecbánya and the Danube river, but the territory around the town of Korpona was added only at the end of the 19th century.

From 1552 to 1685, most of the county was part of the Ottoman Empire and belonged to the administrative unit called Nógrád sandjak.

In the aftermath of World War I, most of Hont county became part of newly formed First Czechoslovak Republic (Czechoslovakia), as recognized by the concerned states in 1920 by the Treaty of Trianon.

After World War II, the Trianon borders were restored and Nógrád-Hont County was reformed on her remnants in Hungary.

In 1993, Czechoslovakia was split and in 1996 its territory became part of the newly created Nitra and Banská Bystrica regions of Slovakia.