River basin environmental diagnosis and monitoring are fundamental for water resource use and conservation plans, as these systems integrate different landscape elements and may undergo impacts and changes of different levels and scales. In this context, this work aimed to characterize the geospatial, morphometric, and environmental dynamics in the Mariana microbasin, in the municipality of Alta Floresta, to provide technical-scientific subsidies for environmental management and planning at a local and regional level. The microbasin was analyzed for morphometric, topographic, and land-use and cover parameters using geospatial data processed in a geographic information system. The microbasin is classified as fourth-order, has a network of 72 channels, and its relief is mostly flat and smooth wavy. Moreover, the soil is predominantly covered by agricultural lands, encompassing 70% of the area. This feature brings the need to adopt conservation practices for soil management. This study showed the need for continuous environmental monitoring programs and expansion of conservation actions in the studied area.