# December 6, 1950 — NE of Limestone, ME — Radar-Inspired National Alert

**URL:** https://uapdiscovery.discourse.group/t/december-6-1950-ne-of-limestone-me-radar-inspired-national-alert/421
**Category:** Blue Book Unknowns
**Created:** [December 5, 2025, 9:52pm UTC](https://uapdiscovery.discourse.group/t/december-6-1950-ne-of-limestone-me-radar-inspired-national-alert/421 "2025-12-05T21:52:43Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![jeffknox](https://avatars.discourse-cdn.com/v4/letter/j/e47c2d/32.png) [@jeffknox](https://uapdiscovery.discourse.group/u/jeffknox)
#### Post date: [December 5, 2025, 9:52pm UTC](https://uapdiscovery.discourse.group/t/december-6-1950-ne-of-limestone-me-radar-inspired-national-alert/421/1 "2025-12-05T21:52:43Z")

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![12061950-NELimestoneME-AirAlert-1](https://canada1.discourse-cdn.com/flex011/uploads/uapdiscovery/original/2X/a/ae0ecd1ea951b793cfab5207155f3c827019e8ff.jpeg)

December 6, 1950 — NE of Limestone, ME  
10:30–11:04 a.m. The ConAC Air Defense Controller notifies the HQ USAF that a number of unidentified aircraft are approaching the northeast area of the United States and that there is no reason to believe they are friendly. By radar contact it is determined that approximately 40 aircraft are in the flight at 32,000 feet on a course of 200° northeast of Limestone, Maine. The White House is notified at 10:31 a.m., and President Truman discusses the reports in a meeting with UK Prime Minister Clement Attlee. [Eberhart]

Additional Documents:

 ![12061950-NELimestoneME-AirAlert-2](https://canada1.discourse-cdn.com/flex011/uploads/uapdiscovery/original/2X/e/e89a308954c1efb2148491ddb1812f5012c22060.jpeg)

 ![12061950-NELimestoneME-AirAlert-3](https://canada1.discourse-cdn.com/flex011/uploads/uapdiscovery/original/2X/6/62faeedf72d7ecbcaed584ffa878a12e9af14ef9.jpeg)

Sources:  
Brad Sparks, Blue Books Unknowns Catalogue, Case 423, p. 103;

 ![12061950-NELimestoneME-Sparks-Case423-p103](https://canada1.discourse-cdn.com/flex011/uploads/uapdiscovery/original/2X/7/7fdcbbcb5de3ba19a6bb1befb9cc82fba12de79c.png)

Jerome Clark, The UFO Encyclopedia, 3rd Ed., p. 824;  
Jerome Clark, The UFO Encyclopedia, 4th Ed., p. 892;

 ![12061950-NELimestoneME-ClarkIII-p824](https://canada1.discourse-cdn.com/flex011/uploads/uapdiscovery/original/2X/2/2dd6af9b969f4c49c32e0cb98ec1529c47f47f88.png)

NICAP, “Radar-Inspired National Alert”;

> **[UFO Report](http://www.nicap.org/501206rina_dir.htm)**

Bruce Maccabee, “Immediate Saucer Alert! The Mystery of December 6, 1950,” July 1999;

 ![12061950-NELimestoneME-MaccabeeAbstract](https://canada1.discourse-cdn.com/flex011/uploads/uapdiscovery/original/2X/4/41fffc43bb9ad669a055dc52d504a1d10580a210.png)

> **[Radar Inspired National Alert - Maccabee](http://www.nicap.org/reports/rina4.htm)**