The US Fish and Wildlife Service (USFWS) has an interest in completing the fine-scale vegetation mapping of the remainder of the Simi Valley-Santa Susana Mountains Ecological Subsection of the Southern California Coast Ecological Section (total Project size approximately 155,519 acres). Aerial Information Systems, Inc. (AIS), under a separate contract with the National Park Service (NPS), had completed a large portion of the subsection as part of Santa Monica Mountains National Recreation Area (SAMO) vegetation mapping effort. However, USFWS has had limited funding available so the Project was divided into multiple parts based on funding allotments. Phase 1 - previously allocated funding to develop the floristic classification and mapping of 28,900 acres, conducted in 2019, Phase 2 - current allocation of funds to map an additional 48,700 acres, conducted in 2021-23, and “Future Funding” Phases that are required to map the remainder of the area and expand the classification development to include the Northeast Extension Area when funding becomes available. Protocols comply with state and national standards as defined by the Survey of California Vegetation (SCV) and the US National Vegetation Classification (USNVC).The data collection task for Phase 1 was conducted by California Native Plant Society (CNPS). CNPS collected 80 surveys in the data collection process. For Phase 2, AIS in collaboration with USFWS determined the study area for mapping. The study area was divided into three working modules. All pertinent materials and data files were acquired. The base for mapping was the 2020 NAIP natural color and color infrared imagery. The 2018 NAIP imagery (used for Phase 1), as well as Google Earth, was also available for reference. Fire perimeter files, the Phase 1 classification survey data, land access files, road files, and geology were also obtained. For the Phase 1 and 2 mapping, established statewide standard guidelines are used. Statewide standard for minimum mapping unit (MMU) size is 1 acre for upland types and ¼ acre for wetland and riparian types. The Phase 1 and 2 data completed thus far is not considered a “final” product since ground-truth reconnaissance of Phase 1, accuracy assessment (AA), final data processing and the overall Project final report and metadata creation have not been funded. However, users may find the interim data useful for habitat modeling and/or other land management planning purposes. Additional information can be found in the Phase 1 Final Performance Report here: https://www.cnps.org/wp-content/uploads/2023/12/SantaSusanaMappingReport_Phase-I_Dec2019.pdf. More information can be found in the 2023 project report, which is bundled with the vegetation map published for BIOS here: https://filelib.wildlife.ca.gov/Public/BDB/GIS/BIOS/Public_Datasets/3100_3199/ds3131.zip