The National Blue Trail is a national trail in Hungary, for most of its length part of the European Long Distance Walking Route E4. The route starts atop the Írott-kő Mountain on the Austrian-Hungarian border then leads across Hungary eventually ending 1,170 km later at the village of Hollóháza by the Hungarian-Slovakian border.. The name of the Kéktúra is a reference to the marking of the path itself: it is a horizontal blue stripe on a white rectangle. All segments of the trail are freely accessible to the public; no fees have to be paid or permits obtained, there is only one ferry to take over the Danube between Visegrád and Nagymaros where you have to purchase a ticket. Although to have an official completion, you have to purchase a stamping brochure from MTSZ, the organizer of the trail.

Mátraverebély is a village in Nógrád County, Hungary, beside of the Zagyva river, between the Cserhát and Mátra mountain ranges. As of 2022 census, it has a population of 1752. The main road 21 go across the village, which located beside of the Hatvan–Fiľakovo railway line and 38.4 km away from the M3 motorway. The village have an own railway stop with public transport.