Allocated but unannounced space
Every block here was allocated or assigned by a regional internet registry, and none of them appeared in any routing table we collected at our last snapshot — neither as a route of their own, nor covered by a larger announcement, nor carved up into more specifics.
“Unannounced” does not mean “unused”
Plenty of allocated space is deliberately kept off the public internet: private interconnects, lab and lawful-intercept ranges, networks reachable only inside one operator, and space held in reserve. Some of it is announced somewhere our collectors cannot see, which is a limit of our vantage points rather than a fact about the block.
It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today. Nothing on this page means a block is unallocated, available, or free to announce.
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Countries with the most unannounced blocks, largest first.
Unannounced blocks in United States
27,014 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 209.17.192.0/19 | 8.2k | ARIN |  US | 28th Feb 1997 |
| 209.17.224.0/19 | 8.2k | ARIN | US | 21st Aug 2000 |
| 209.173.56.0/23 | 512 | ARIN | US | 21st Mar 2001 |
| 209.173.59.0/24 | 256 | ARIN | US | 21st Mar 2001 |
| 209.173.60.0/22 | 1k | ARIN | US | 21st Mar 2001 |
| 209.176.0.0/16 | 65.5k | ARIN | US | 20th Nov 1997 |
| 209.177.178.0/23 | 512 | ARIN | US | 4th Jun 2008 |
| 209.177.180.0/22 | 1k | ARIN | US | 4th Jun 2008 |
| 209.177.184.0/21 | 2k | ARIN | US | 4th Jun 2008 |
| 209.177.76.0/24 | 256 | ARIN | US | 31st Jul 2025 |
| 209.177.78.0/24 | 256 | ARIN | US | 11th Sept 2017 |
| 209.178.202.0/24 | 256 | ARIN | US | 30th Sept 2024 |
| 209.178.240.0/22 | 1k | ARIN | US | 16th Jan 2024 |
| 209.178.247.0/24 | 256 | ARIN | US | 7th Sept 2023 |
| 209.178.248.0/22 | 1k | ARIN | US | 7th Sept 2023 |
| 209.18.0.0/19 | 8.2k | ARIN | US | 13th Jan 1997 |
| 209.182.0.0/18 | 16.4k | ARIN | US | 1st Dec 1997 |
| 209.182.128.0/19 | 8.2k | ARIN | US | 17th Feb 2016 |
| 209.182.176.0/20 | 4.1k | ARIN | US | 21st Jun 2002 |
| 209.182.64.0/19 | 8.2k | ARIN | US | 2nd Dec 1997 |
| 209.188.104.0/23 | 512 | ARIN | US | 21st Mar 2001 |
| 209.188.111.0/24 | 256 | ARIN | US | 21st Mar 2001 |
| 209.188.96.0/23 | 512 | ARIN | US | 21st Mar 2001 |
| 209.191.138.0/23 | 512 | ARIN | US | 11th Feb 1998 |
| 209.191.161.0/24 | 256 | ARIN | US | 11th Feb 1998 |
| 209.195.236.0/22 | 1k | ARIN | US | 14th Apr 2026 |
| 209.196.76.0/22 | 1k | ARIN | US | 6th Sept 2000 |
| 209.196.96.0/19 | 8.2k | ARIN | US | 17th Jun 2026 |
| 209.201.128.0/17 | 32.8k | ARIN | US | 7th Sept 2001 |
| 209.202.240.0/20 | 4.1k | ARIN | US | 22nd May 2000 |
| 209.203.224.0/19 | 8.2k | ARIN | US | 7th Sept 2021 |
| 209.204.112.0/22 | 1k | ARIN | US | 16th Mar 1998 |
| 209.204.116.0/24 | 256 | ARIN | US | 13th Apr 2026 |
| 209.206.40.0/21 | 2k | ARIN | US | 2nd Mar 2017 |
| 209.209.100.0/22 | 1k | ARIN | US | 6th Apr 2021 |
| 209.209.108.0/22 | 1k | ARIN | US | 23rd Apr 2021 |
| 209.209.127.0/24 | 256 | ARIN | US | 7th Apr 2021 |
| 209.209.14.0/24 | 256 | ARIN | US | 1st Jul 2026 |
| 209.209.224.0/19 | 8.2k | ARIN | US | 21st Feb 2017 |
| 209.209.27.0/24 | 256 | ARIN | US | 13th Apr 2021 |
| 209.209.73.0/24 | 256 | ARIN | US | 6th Apr 2021 |
| 209.217.128.0/18 | 16.4k | ARIN | US | 5th Dec 2000 |
| 209.221.128.0/18 | 16.4k | ARIN | US | 5th May 1998 |
| 209.222.112.0/23 | 512 | ARIN | US | 15th Aug 2025 |
| 209.222.72.0/22 | 1k | ARIN | US | 6th Mar 2015 |
| 209.224.0.0/16 | 65.5k | ARIN | US | 13th Apr 1998 |
| 209.225.64.0/19 | 8.2k | ARIN | US | 24th May 2000 |
| 209.228.0.0/14 | 262k | ARIN | US | 26th Dec 2019 |
| 209.23.48.0/20 | 4.1k | ARIN | US | 25th Aug 2026 |
| 209.234.112.0/20 | 4.1k | ARIN | US | 9th Feb 2005 |