Methodology & Sources
Everything on this site is derived from public GIS endpoints and a documented, reproducible pipeline. No scraped third-party summaries; no proprietary data.
Data sources
- Salt Lake County Assessor — Parcelshttps://apps.saltlakecounty.gov/slcogis/rest/services/Land/MapServer/1
397,702 parcels. The only public layer carrying owner of record, plus acreage, improvement (building) market value, building sq ft, year built, exempt type, and tax district. 2026 tax year.
- Salt Lake City Zoning GIShttps://services.arcgis.com/mMBpeYj0vPFotzbe/arcgis/rest/services/zoning/FeatureServer/5
4,852 zoning polygons with district code and name, published by SLC Open Data.
- UGRC Municipal Boundarieshttps://services1.arcgis.com/99lidPhWCzftIe9K/arcgis/rest/services/UtahMunicipalBoundaries/FeatureServer/0
Lt. Governor-certified municipal boundaries; 23 municipalities and metro townships in Salt Lake County.
- UGRC LIR Parcels — Summit & Utah Countieshttps://services1.arcgis.com/99lidPhWCzftIe9K/arcgis/rest/services/Parcels_Summit_LIR/FeatureServer/0
Summit County (37,294 parcels) and Utah County (327,655 parcels, Parcels_Utah_LIR) with acreage, market values, building sq ft, and city — but no owner names, which is why ownership analysis covers Salt Lake County only.
Processing rules
Projection.All area math is performed in NAD83 / UTM Zone 12N (EPSG:26912). Acreage uses the assessor's parcel_acres field, falling back to geometry-derived area only where the assessor value is missing or zero.
Zoning assignment. Each parcel is assigned to the zoning district containing its representative point. Edge parcels that miss (325) are assigned by largest polygon overlap; 356 parcels (0.5%) fall in zoning-map gaps — mostly right-of-way slivers — and are labeled UNZONED/ROW.
Structure vs. vacant.A parcel is "built" if its assessor improvement (building) market value exceeds $0 or its building square footage exceeds zero; otherwise vacant. In Summit and Utah counties, improvement value is derived as total market value minus land value from LIR records. Caveat: fully tax-exempt parcels can show $0 improvement value even where structures exist, and in rural areas "no structure" includes greenbelt and agricultural land.
City-owned classification. Includes Salt Lake City Corporation in all recorded spelling variants plus component entities: Department of Airports, Public Utilities, Division of Housing, Municipal/Local Building Authority, Redevelopment Agency / Community Reinvestment Agency, and the SLC Public Library. Excludes separate legal entities that merely contain "Salt Lake City" in their names: the School District/Board of Education, Housing Authority, Metropolitan Water District, Mosquito Abatement District, the City of South Salt Lake, and private companies. Joint city/county or city/private holdings are included and flagged.
County-owned classification. Includes Salt Lake County and variants (Flood Control, Tax Deed, Auditor, Real Estate, Recreation Board), the County Library, and the county's Municipal Building Authority. Excludes the county Housing Authority, water conservancy and sanitation districts, Service Area No. 3, the State of Utah, and private entities. Joint holdings included and flagged.
Boundary tests.A parcel's location is judged by its representative point against UGRC-certified boundaries: city-owned parcels against the Salt Lake City limit; county-owned parcels against all 23 municipal boundaries, with the remainder classed as unincorporated. Summit and Utah county parcels are grouped by the assessor's recorded parcel city.
Known limitations
- Owner-of-record analysis covers Salt Lake County only — Summit and Utah county assessors do not publish owner names in public GIS, and Salt Lake City's watershed holdings in Davis, Morgan, Summit, Tooele, and Wasatch counties therefore require records requests to those county assessors.
- Parcel boundaries are assessment-grade, not survey-grade; do not use for legal boundary determinations.
- Owner-of-record strings contain typos as recorded (e.g., "CORPROATION"); classification matches all observed variants.
Data pulled July 2026. Questions about the pipeline or the underlying data? See the datasets on the downloads page — each workbook includes its own methodology tab.