EPSG:4267 — NAD27
NAD27 — the legacy U.S. horizontal datum used in older USGS quads, deeds, and pre-1986 surveys.
PROJ definition
+proj=longlat +datum=NAD27 +no_defs +type=crs
Geographic bounds
W 167.65° S 7.15° E -47.74° N 83.17°
Convert coordinates with EPSG:4267
Official EPSG transformations for NAD27
Datum transformations involving EPSG:4267 published in the EPSG dataset, with parameters, accuracy and area of use:
About EPSG:4267
EPSG:4267 is the geographic CRS for the North American Datum of 1927 (NAD27), built on the Clarke 1866 ellipsoid with origin at Meades Ranch, Kansas. It was the official datum for U.S. and Canadian mapping until NAD83 superseded it in the late 1980s.
Converting between NAD27 and NAD83/WGS84 is non-trivial because the underlying ellipsoid and origin differ — the shift varies regionally from a few metres to over 100 metres across the continent. Accurate conversion requires the NADCON grid-shift files; a Helmert seven-parameter transformation gives only an approximation. Browser-based tools, including this one, generally do not perform NTv2/NADCON grid shifts, so for legal or surveying-grade NAD27 conversions use a desktop GIS with the appropriate grids installed.
Despite being deprecated for new work, NAD27 references persist in surveying records, public-land deeds, oil and gas leases, and historical archives.
Common use cases
- Reading legacy USGS topographic maps (pre-1980s)
- Interpreting old deeds and survey records
- Migrating historical geological / mining datasets
Common transformations from EPSG:4267
- EPSG:4267 → EPSG:4326NAD27 → WGS 84
- EPSG:4267 → EPSG:3857NAD27 → WGS 84 / Pseudo-Mercator
- EPSG:4267 → EPSG:3395NAD27 → WGS 84 / World Mercator
- EPSG:4267 → EPSG:4978NAD27 → WGS 84
- EPSG:4267 → EPSG:7789NAD27 → ITRF2014
- EPSG:4267 → EPSG:4269NAD27 → NAD83
- EPSG:4267 → EPSG:6318NAD27 → NAD83(2011)
- EPSG:4267 → EPSG:4322NAD27 → WGS 72
- EPSG:4267 → EPSG:26910NAD27 → NAD83 / UTM zone 10N
- EPSG:4267 → EPSG:26911NAD27 → NAD83 / UTM zone 11N
- EPSG:4267 → EPSG:26912NAD27 → NAD83 / UTM zone 12N
- EPSG:4267 → EPSG:26913NAD27 → NAD83 / UTM zone 13N
Frequently asked questions
- Why do my NAD27 coordinates differ so much from NAD83?
- The two datums use different ellipsoids and origins. Differences range from a few metres to over 100 m depending on location. Always perform a proper datum transformation; never treat them as equivalent.
- How accurate is a Helmert conversion from NAD27?
- Single-grid Helmert parameters give 1-5 m accuracy across CONUS — fine for visualisation, not for surveying. For sub-metre work apply the NADCON grid-shift transformation.
- What is the proj4 string for EPSG:4267?
- The proj4 definition for EPSG:4267 is: +proj=longlat +datum=NAD27 +no_defs +type=crs
- Where is EPSG:4267 used?
- EPSG:4267 (NAD27) is defined for the area: North America - NAD27.