Building or using a crane near Garrison Dam Recreational Airpark (37N)?
Garrison Dam Recreational Airpark in Riverdale, North Dakota is a public-use airport. Under 14 CFR 77.9, anything within 10,000 feet of its runways that rises above a 50:1 slope needs FAA Form 7460-1 at least 45 days before construction. Check your exact site free.
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How tall can you build near 37N without filing?
The notice surface rises 1 foot for every 50 feet of horizontal distance from the nearest point of the nearest runway, starting at the runway's elevation. Using the lowest runway-end elevation, 1,704 ft above sea level:
| Distance from nearest runway | Notice required above (height over 1,704 ft) | …which is this elevation (AMSL) |
|---|---|---|
| 250 ft | 5 ft | 1,709 ft |
| 500 ft | 10 ft | 1,714 ft |
| 1,000 ft | 20 ft | 1,724 ft |
| 2,000 ft | 40 ft | 1,744 ft |
| 3,000 ft | 60 ft | 1,764 ft |
| 5,000 ft | 100 ft | 1,804 ft |
| 7,500 ft | 150 ft | 1,854 ft |
| 10,000 ft | 200 ft | 1,904 ft |
| Beyond 10,000 ft | Only the 200-ft-above-ground rule applies (77.9(a)) | |
If your ground is lower than 1,704 ft you can build taller by the difference; if it's higher, less. Cranes count at their maximum height. The free check above uses USGS ground elevation for your exact spot.
Runways and notice boundary
Dashed line: the 10,000-ft area where the 50:1 notice slope applies; inner line: 5,000 ft.
| Runway | Length | End elevations (ft AMSL) |
|---|---|---|
| 11/29 | 3,195 ft | 1719 / 1704 |
Filing Form 7460-1 near 37N
- File online through the FAA's OE/AAA system at least 45 days before construction or before applying for a building permit, whichever is first. Filing is free.
- You need NAD 83 coordinates, site ground elevation, structure height above ground and above sea level.
- Construction on airport property always needs notice, whatever the height.
More: Do I need to file Form 7460-1? · Cranes and Form 7460-1
Other public-use airports nearby
- D05 — Garrison Muni (10 nm)
- HZE — Mercer County Rgnl (14 nm)
- 5C8 — Washburn Muni (17 nm)
- 91N — Turtle Lake Muni (20 nm)
- 95D — Beulah (22 nm)
- 7G2 — Mc Clusky Muni (37 nm)
Source: FAA airport, runway and runway-end data (NASR cycle effective 2026/10/01). Screening only — the FAA issues determinations.