North Yorkshire is a large county in the region called Yorkshire and the Humber in the north of England.
North Yorkshire was part of one bigger county called Yorkshire. The three parts of Yorkshire used to be called the West Riding, the East Riding, and the North Riding. in 1974, the boundaries and names changed. The "North Riding" changed to "North Yorkshire". The other main parts of Yorkshire are now South Yorkshire, West Yorkshire, and the East Riding of Yorkshire.
The largest city in North Yorkshire is York. York is now (since 1996) a unitary authority, it is not officially part of North Yorkshire.
North Yorkshire is the largest county in England. It has several towns. It also has many open green areas and hills, so two of the 11 UK national parks (the North York Moors and most of the Yorkshire Dales) are in North Yorkshire.