Nowe Miasto County (Polish: powiat nowomiejski) is a unit of territorial administration and local government (powiat) in Warmian-Masurian Voivodeship, northern Poland. It was created on January 1, 1999 as a result of the Local Government Reorganization Act of 1998. Its administrative seat and only town is Nowe Miasto Lubawskie, which lies 73 kilometres (45 mi) south-west of the regional capital Olsztyn.
The county covers an area of 695.01 square kilometres (268.3 sq mi). As of 2006 its total population is 43,388, out of which the population of Nowe Miasto Lubawskie is 11,036 and the rural population is 32,352.