| Cachoeira do Arari | |
| Settlement Type: | Municipality |
| Mapsize: | 250px |
| Subdivision Type: | Country |
| Subdivision Type1: | Region |
| Subdivision Type2: | State |
| Subdivision Name: |  Brazil |
| Subdivision Name1: | North |
| Area Total Km2: | 3102.080 |
| Elevation M: | 2 |
| Population As Of: | 2020 [1] |
| Population Total: | 24,064 |
| Population Density Km2: | 5.7 |
| Coordinates: | -1.0108°N -48.9628°W |
| Timezone: | BRT |
| Utc Offset: | -3 |
| Postal Code Type: | Postal Code |
| Postal Code: | 68840-000 |
Cachoeira do Arari is a Brazilian municipality located in the state of Pará. Its population as of 2020 is estimated to be 24,064 people. The area of the municipality is 3,102.080 km². The city belongs to the mesoregion Marajó and to the microregion of Arari.
The municipality is contained in the Marajó Archipelago Environmental Protection Area, a sustainable use conservation unit established in 1989 to protect the environment of the delta region.