EPSG:4421 · United States
NAD83 / BLM 1N (ftUS) to KML & KMZ
NAD83 / BLM 1N (ftUS) (EPSG:4421) is a Transverse Mercator coordinate system on the NAD83 datum, with coordinates in US survey feet. Its official area of use is: United States (USA) - between 180°W and 174°W - Alaska and offshore continental shelf (OCS).
- Converter already set to EPSG:4421
- Latitude and longitude on WGS 84, as Google Earth uses
- Download the point as KML
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Good to know
- Coordinates are in US survey feet. Enter them in those units, not metres.
- Datum: Treated as WGS 84, no shift (the datums agree to about a metre or better).
Convert a whole spreadsheet
- Open the web app or the Windows app, and paste your rows from Excel or open a CSV file.
- Under Coordinate system, search for “4421” and pick NAD83 / BLM 1N (ftUS).
- Check one point you know on the map, then press Save KML or Save KMZ and open it in Google Earth.
Check points for EPSG:4421
Five points inside the area of use of NAD83 / BLM 1N (ftUS), with their latitude and longitude on WGS 84 and their easting and northing in this grid (US survey feet). Enter an easting and northing in the converter above: you should get the latitude and longitude shown, to a few centimetres.
| Point | Latitude | Longitude | Easting | Northing |
|---|---|---|---|---|
| Middle of the area of use | 55.54500° N | 176.99500° W | 1,641,451.75 | 20,194,976.72 |
| Towards the north-west | 60.14400° N | 178.79800° W | 1,312,845.61 | 21,879,244.84 |
| Towards the north-east | 60.14400° N | 175.19200° W | 1,969,809.29 | 21,879,294.57 |
| Towards the south-west | 50.94600° N | 178.79800° W | 1,226,024.20 | 18,521,482.41 |
| Towards the south-east | 50.94600° N | 175.19200° W | 2,057,113.72 | 18,521,538.74 |
Common mistakes with NAD83 / BLM 1N (ftUS)
- Easting and northing swapped. In NAD83 / BLM 1N (ftUS) the middle of the grid is near easting 1,641,451.75 and northing 20,194,976.72. If your easting column holds numbers like 20,194,976.72, the columns are the wrong way round and every point lands far away: swap them before converting.
- Metres entered as feet. NAD83 / BLM 1N (ftUS) is in US survey feet. Enter the values as they are; converting them to metres first puts every point in the wrong place.
- Forgetting the datum. NAD83 / BLM 1N (ftUS) is not on WGS 84: treated as WGS 84, no shift (the datums agree to about a metre or better). Picking a WGS 84 grid with the same projection instead leaves the points off by that amount.
- Points outside the grid's area. NAD83 / BLM 1N (ftUS) is meant for United States (USA) - between 180°W and 174°W - Alaska and offshore continental shelf (OCS). Points well outside that area convert with growing error; the converter flags them so you can choose the right grid.
- A local site grid. If every point is off by the same distance and direction, the drawing may be on a local site grid. Calibrate on three or more known control points instead.
New to this? Read how to convert easting and northing to latitude and longitude.