What is the SBN file format?
Files with the .sbn extension contain a binary spatial index developed by Esri (Environmental Systems Research Institute). These files are used in Esri ArcGIS for spatial mapping. The .sbn file stores an R-tree index of the Minimum Bounding Rectangles (MBRs) of features from the corresponding .shp file. It is used together with the companion .sbx file - which indexes the .sbn itself - to accelerate data access during spatial queries.
The actual spatial geometry and attributes are held in .shp and .dbf files; the .sbn is a performance index only. A Shapefile dataset represents a collection of geographic objects:
- point,
- line,
- or area (polygon).
These represent, for example, streets, points of interest (POIs), administrative boundaries, or other features used in Geographic Information System (GIS) workflows.
The core files of an Esri Shapefile dataset are .shp, .shx, and .dbf. The .sbn and .sbx files are optional index files that improve query performance. Every file in a dataset shares the same base name with a different extension - for example, roads.shp, roads.shx, and roads.dbf. Files are typically located in the same directory. On Windows, .sbn files may be hidden and not shown by default in File Explorer.
The .sbn index is generated automatically when ArcGIS performs a spatial query on a read-write Shapefile. Deleting it is safe - ArcGIS regenerates it as needed. QGIS uses its own index format (.qix) rather than reading .sbn files directly.
Security & safety
RISK: LOWBinary index file with no executable code. Cannot contain malware. Safe to delete and regenerate.
Format details
in a nutshellPrograms that open SBN files
Windows2 apps
ArcGIS Pro
Paid Open the .shp file in ArcGIS Pro; the .sbn is used automatically for spatial indexing - not opened directly. 
QGIS
Open-source Add the .shp layer via Layer → Add Layer → Add Vector Layer; QGIS ignores .sbn but reads the shapefile correctly. 
macOS1 app
Linux1 app
Technical details
deep spec| File type | Binary spatial index (R-tree) |
| MIME type | application/octet-stream |
| Byte order | big-endian |
| Index structure | R-tree of Minimum Bounding Rectangles (MBRs) for each feature in the companion .shp file |
| Companion index file | .sbx - indexes the .sbn itself; always present alongside the .sbn |
| Role in Shapefile set | Optional performance index; not part of the mandatory .shp/.shx/.dbf triplet |
| Typical file size | 1 KB - several MB (scales with feature count in the Shapefile) |
| Generation | Auto-created by ArcGIS when a spatial query is performed on a read-write Shapefile |
| Safe to delete | Yes - ArcGIS regenerates the .sbn automatically when needed |
| QGIS behaviour | QGIS ignores .sbn; it generates its own .qix spatial index instead |
| Spec status | Proprietary and undocumented by Esri; structure reverse-engineered by the open-source GIS community |
| Paired with | .shp, .shx, .dbf (mandatory Shapefile triplet) plus optional .prj, .cpg, .sbx |
| Superseded by | GeoPackage (.gpkg) and GeoJSON recommended for new workflows; .sbn remains in heavy use with legacy Shapefile data |
| Released | early 1990s (with the Esri Shapefile format, ArcView era) |
| Latest version | No versioned spec; format stable and unchanged since introduction |
SBN conversions
Community Q&A
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