Posio is a municipality of Finland.
It is located in the province of Lapland. The municipality has a population of 2,888
(31 August 2024) and covers an area of 3,544.90 square kilometres (1,368.69 sq mi) of
which 506.14 km2 (195.42 sq mi)
is water. The population density is
0.95 inhabitants per square kilometre (2.5/sq mi). Neighbour municipalities are Rovaniemi, Kemijärvi, Ranua, Salla, Kuusamo, Taivalkoski and Pudasjärvi.
The municipality has a single language, Finnish.
Major employers in Posio are the municipality itself, a major pottery manufacturer Pentik and agriculture (especially dairy farming).
The European route E63 runs through the northern-eastern parts of the municipality.
Korouoma canyon and natural reserve is located in Posio.
8 kilometres (5.0 mi) north of the center of Posio is a microstate called Valtio, founded by Ari "Paska" Peltonen in 2006.