NAD83(2011) – EPSG:6318
May 14,2026

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Introduction

NAD83(2011) – EPSG:6318 is the most recent realization of the North American Datum of 1983 (NAD83), released by the U.S. National Geodetic Survey (NGS) in 2011 as part of the National Spatial Reference System (NSRS). It succeeded NAD83(NSRS2007) and represents the culmination of over a decade of GPS observations from approximately 2,000 Continuously Operating Reference Stations (CORS) and thousands of passive control marks. NAD83(2011) achieved improved alignment with the International Terrestrial Reference Frame (ITRF2008) while maintaining the plate-fixed nature of NAD83. It is currently the official NSRS realization recommended by the NGS for high-precision surveying, mapping, and GIS applications across the United States.

Coordinate System Composition

NAD83(2011) – EPSG:6318 consists of the following main components:

Origin: Earth's center of mass, fixed to the North American tectonic plate.
Reference Ellipsoid: GRS 1980 (semi-major axis: 6,378,137.0 m; flattening: 1/298.257222101).
Coordinate Representation: Two-dimensional geographic coordinates (latitude, longitude).
Reference Network: Based on ~2,000 CORS stations and tens of thousands of passive control marks, adjusted in a single, nationwide least-squares solution.
Plate Fixing: Fixed to the North American plate – coordinates do not drift with tectonic motion.
ITRF Alignment: Adjusted to be consistent with ITRF2008 at the epoch 2010.00, improving compatibility with global positioning systems.

Pros

Highest accuracy among NAD83 realizations: NAD83(2011) offers the best positional accuracy of any NAD83 version, with network accuracies of approximately 0.005–0.01 meters (5–10 mm) for CORS stations and 0.01–0.05 meters for passive control marks, making it suitable for the most demanding surveying and engineering applications.
Improved ITRF alignment: By aligning with ITRF2008 at epoch 2010.00, NAD83(2011) provides much better compatibility with global frames such as WGS84 and ITRF than earlier NAD83 realizations. This reduces transformation complexity and error when integrating GPS data (which natively uses ITRF/WGS84) with NSRS data.
Plate-fixed stability for legal applications: Like all NAD83 realizations, NAD83(2011) is fixed to the North American tectonic plate. Coordinates do not drift over time, simplifying legal boundary descriptions, cadastral records, property surveys, and long-term infrastructure management, as no epoch tracking is required.
Nationwide consistency: The single, unified adjustment eliminates boundary discontinuities that existed between state-by-state HARN adjustments, ensuring seamless coordinates across state lines and consistent precision from coast to coast, including Alaska, Hawaii, Puerto Rico, and other territories.
Large and growing data footprint: As the current official NSRS realization, NAD83(2011) is the standard for new data collection by U.S. federal agencies (USGS, Census, FEMA), state governments, and local municipalities. Most newly published GIS data in the United States uses EPSG:6318.
Standard software support: EPSG:6318 is fully supported as a native coordinate system in all major GIS platforms (ArcGIS Pro, QGIS), surveying software (Trimble, Leica), and geodetic tools, making it immediately accessible for practical work.
Official NGS recommendation: The National Geodetic Survey explicitly recommends NAD83(2011) for all high-precision surveying, mapping, and GIS applications requiring the NSRS, providing official guidance and transformation tools.

Cons

Two-dimensional only: EPSG:6318 defines only geographic coordinates (latitude, longitude) without a height component. For three-dimensional applications requiring vertical information, a separate vertical datum such as NAVD88 or a geoid model (e.g., GEOID18) must be combined, adding complexity to 3D and 4D workflows.
Regional scope limitation: NAD83(2011) is strictly limited to North America (United States, Canada, Mexico, and Caribbean territories). It is completely unsuitable for global datasets, international applications, or mapping projects that cross into South America, Europe, or other tectonic plates.
Not fully aligned with modern ITRF: While aligned with ITRF2008 (circa 2010), NAD83(2011) does not reflect the latest ITRF realizations such as ITRF2014 or ITRF2020. For users requiring alignment with the most current global frames, additional transformation steps are necessary.
Epoch-dependent transformations to ITRF: Although improved over NSRS2007, the transformation between NAD83(2011) and ITRF/WGS84 still depends on observation epoch due to North American plate motion (~2–3 cm/year drift). For applications requiring centimeter-level accuracy, the epoch must be tracked and applied correctly.
Impending replacement by modernized NSRS: The NGS plans to replace all NAD83 realizations (including NAD83(2011)) with a new, entirely modernized NSRS based on ITRF and incorporating a new geometric datum (Atlantic-Pacific 2022) and a new vertical datum (Pacific-Pacific 2022). This transition, currently scheduled for 2025–2026, will eventually render NAD83(2011) obsolete for new work.
Learning curve for ITRF users: Users accustomed to global frames (ITRF, WGS84) must understand the differences in reference frame definition, plate fixation, and epoch handling. Misunderstanding these differences can lead to coordinate errors of several meters when mixing data from different frames.

Application Scenario

NAD83(2011) is the current standard for high-precision GIS, surveying, and mapping applications across the United States and its territories. It is widely used in cadastral surveying (property boundaries), engineering and construction (road, bridge, and building projects), federal and state GIS databases (USGS topographic maps, Census Bureau TIGER data, FEMA flood maps), utility infrastructure management (pipelines, power lines, telecommunications), environmental monitoring (wetland delineation, forest management), and transportation networks (highways, railways, airports). As the official NGS-recommended NSRS realization, NAD83(2011) is the appropriate choice for any new project requiring the highest accuracy within the NAD83 framework. However, users should be aware of the upcoming transition to the modernized NSRS and plan for eventual migration to the new datums scheduled for 2025–2026.