Wikipedia
Trøndelag is a geographical region in the central part of Norway, consisting of the two counties Nord-Trøndelag and Sør-Trøndelag. It also formerly also included the county of Jämtland, which is today part of Sweden; it is therefore also known unofficially as Øst-Trøndelag. The districts of Nordmøre and Romsdal, and the municipality of Bindal, were also originally parts of Trøndelag - and the inhabitants there still speak dialects similar to Trøndersk. The region is, together with Møre og Romsdal, part of a larger administrative division called Central Norway.
A person from Trøndelag is called a Trønder. The largest city, unofficial capital of Trøndelag and also the first capital of Norway, is Trondheim (Sør-Trøndelag). The dialect spoken in the area is characterized by dropping out most vowel endings; see apocope.
The region was divided into two administrative counties in 1804. In 2016, the two county councils voted to merge into a single county in 2018.