| Colniza | |
| Official Name: | The Municipality of Colniza |
| Settlement Type: | Municipality |
| Mapsize: | 250px |
| Coordinates: | -9.5439°N -57.4489°W |
| Subdivision Type: | Country |
| Subdivision Name: |  Brazil |
| Subdivision Type1: | Region |
| Subdivision Name1: | Central-West |
| Subdivision Type2: | State |
| Subdivision Name2: | Mato Grosso |
| Established Title: | Founded |
| Established Date: | November 26, 1998 |
| Leader Title: | Mayor |
| Leader Name: | Sergio Bastos Dos Santos (PMBD) |
| Area Total Km2: | 27.947.646 |
| Elevation M: | 0 |
| Population Total: | 39,861 |
| Population As Of: | 2020 [1] |
| Population Density Km2: | 0.5 |
| Timezone: | BRT |
| Utc Offset: | -3 |
Colniza is a municipality in the state of Mato Grosso, Brazil.
Colniza has the highest homicide rate in Brazil with 165 deaths per year per 100 thousand inhabitants.It is the westernmost and largest (by area) municipality of the state.
The municipality of Colniza has a mosaic of conservation units consisting of the Rio Madeirinha Ecological Station, the Rio Roosevelt Ecological Station, the Tucumã State Park and the Guariba-Roosevelt Extractive Reserve.
Satellite monitoring showed that Colniza had the highest level of deforestation in Mato Grosso in the six years from 2010 to 2016, with cleared, most of it illegally. Rates of deforestation rose successively in 2013, 2014 and 2015.
The Rio Madeirinha Ecological Station is a fully protected environmental unit created in 1997.The Rio Roosevelt Ecological Station is a strictly protected conservation unit created in 1997.The Guariba-Roosevelt Extractive Reserve is a sustainable use unit created in 1996.The municipality also contains of the Campos Amazônicos National Park, a protected area created in 2006 that protects an unusual enclave of cerrado vegetation in the Amazon rainforest.It contains 44% of the Igarapés do Juruena State Park, created in 2002.