The oldest trustworthy preserved written memoirs about Veľký Krtíš are from second third of the 13th century. This is not late, because even in surrounding countries this was time when began more regular and in a big amount to originate documents, right from the 13th century. The title itself „Krtíš“ appeared for the first time in the document released by the Royal Office the 9th of September 1245. From that document we know that certain Martin Bán, before the Tatar invasion occurred, he had given a vast estate in the south of Slovakia to the Šahy´s monastery and it was confirmed by the king Belo IV. He Himself again confirmed this ownership to the monastery in year 1245. Among given estates was a present village Dolné Plachtince, whose boarder was limited by the Krtíš´s creek, in this historical source marked as „Curtus“.
About the origin of the name „Krtíš“ (latin: Curtus, Kurtus, Kurthes) there is among the historians, linguists and others experts even until now not a unified opinion where it origins and it is still an open question.
During all those periods documented in many writings there were many times the periods of flourishing as well as periods of bankruptcy and mischief. The Tatar pillage in the first half of 13th century was the first big historical event and from that moment this originally a service settlement of the king´s castle and the headquarters of Novohrad, Veľký Krtíš started to write its own history.
This village was situated on a very important medieval transport and business route known as „The great route“. In 16th and 17th century was this region exposed to the attacks of the Turkish invasion of the Ottoman Empire and also of the Hungarian Estates Uprisings. In the years 1554-1593 was village Veľký Krtíš under the Turk´s administration and was part of the Novohrad´s Sandzak. In the first half of 17th century up until 1680 was Krtíš almost destroyed and depopulated.
More favorable development of settlement Veľký Krtíš occurred after abolition of subjection in 19th century. From 1854 till 1864 began development of local mining, there opened first Brauncoal mine between villages Malý Krtíš and Veľký Krtíš by a couple of local landowners Andrej Mešš and Viliam Sebastiani and his company.
A whole new period of development of Veľký Krtíš and also his wider neighborhood started after 1945, when state renewed mining of coal, at the earliest in Malé Straciny then in 1948 in Pôtor and from 1962 in the plant “Dolina“Veľký Krtíš.
In 1950 this development caused that in Veľký Krtíš state began to build the block of flats for miners and their families and started a big change from village into a town, firstly as housing development and later became a small town.
In 1960 again we see the decline of mining and this stagnation caused cancellation of the district Modrý Kameň and connection of the district to the neighboring territorial unit. This caused further cultural and economical recession. That’s why in 1968 a new decision was made and the state authorities created a new district with headquarters in Veľký Krtíš. This new administrative move contributed to a radical and rapid development of the settlement. There has been development of a new industries ever since. Beside of the mining there have developed industries like the machinery, food, textile, construction and others.