Fire severity is a metric of the loss of biomass caused by fire. In collaboration with the NSW Rural Fire Service, DCCEEW Remote Sensing & Regulatory Mapping team has developed a semi-automated approach to mapping fire extent and severity through a machine learning framework based on satellite imagery. The method uses standardised classes to allow comparison of different fires across the landscape. The FESM severity classes include: unburnt, low severity (burnt understory, unburnt canopy), moderate severity (partial canopy scorch), high severity (complete canopy scorch, partial canopy consumption), extreme (full canopy consumption). Here we provide historical severity mapping for 8 priority regions on National Parks land tenure from 1989/90 to 2015/16, which is based on Landsat satellite imagery. This covers approximately 30% of the NPWS Managed Lands, across a wide range of vegetation types. From 2016/17 to the current fire year, these regions are covered in the statewide FESM data, which is based on Sentinel 2 satellite imagery. Ongoing FESM processing aims to achieve statewide coverage back to 1989/90, in staged released, as resources permit.