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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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.
Browse by registry
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Countries with the most unannounced blocks, largest first.
Unannounced blocks in United States
26,989 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 141.206.160.0/19 | 8.2k | ARIN |  US | 16th Oct 1992 |
| 141.224.112.0/20 | 4.1k | ARIN | US | 14th Jun 2024 |
| 141.226.138.0/24 | 256 | ARIN | US | 6th Jul 2017 |
| 141.240.0.0/16 | 65.5k | ARIN | US | 10th Aug 1990 |
| 141.247.0.0/16 | 65.5k | ARIN | US | 21st Jun 1994 |
| 141.251.0.0/16 | 65.5k | ARIN | US | 22nd Jun 2011 |
| 142.0.68.0/22 | 1k | ARIN | US | 26th Jun 2024 |
| 142.11.128.0/18 | 16.4k | ARIN | US | 19th Jun 2012 |
| 142.11.64.0/18 | 16.4k | ARIN | US | 19th Jun 2012 |
| 142.147.14.0/24 | 256 | ARIN | US | 24th Aug 2015 |
| 142.202.106.0/24 | 256 | ARIN | US | 20th Dec 2019 |
| 142.202.155.0/24 | 256 | ARIN | US | 26th Jun 2024 |
| 142.202.156.0/24 | 256 | ARIN | US | 21st Jan 2020 |
| 142.202.159.0/24 | 256 | ARIN | US | 8th Jan 2020 |
| 142.202.176.0/22 | 1k | ARIN | US | 4th Feb 2020 |
| 142.202.184.0/24 | 256 | ARIN | US | 18th Dec 2019 |
| 142.202.199.0/24 | 256 | ARIN | US | 8th Jan 2020 |
| 142.202.236.0/22 | 1k | ARIN | US | 27th Dec 2019 |
| 142.202.4.0/22 | 1k | ARIN | US | 18th Dec 2019 |
| 142.202.66.0/24 | 256 | ARIN | US | 14th Jan 2020 |
| 142.202.8.0/24 | 256 | ARIN | US | 19th Dec 2019 |
| 142.202.81.0/24 | 256 | ARIN | US | 19th Dec 2019 |
| 142.202.89.0/24 | 256 | ARIN | US | 20th Dec 2019 |
| 142.228.48.0/22 | 1k | ARIN | US | 11th Aug 2026 |
| 142.248.108.0/23 | 512 | ARIN | US | 14th Oct 2025 |
| 142.248.110.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.112.0/22 | 1k | ARIN | US | 14th Oct 2025 |
| 142.248.127.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.132.0/22 | 1k | ARIN | US | 10th Oct 2025 |
| 142.248.158.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 142.248.164.0/22 | 1k | ARIN | US | 10th Oct 2025 |
| 142.248.168.0/22 | 1k | ARIN | US | 13th Oct 2025 |
| 142.248.189.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.196.0/22 | 1k | ARIN | US | 10th Oct 2025 |
| 142.248.204.0/23 | 512 | ARIN | US | 10th Oct 2025 |
| 142.248.206.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.207.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.208.0/22 | 1k | ARIN | US | 10th Oct 2025 |
| 142.248.220.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.223.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.24.0/22 | 1k | ARIN | US | 10th Oct 2025 |
| 142.248.250.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.251.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.252.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.253.0/24 | 256 | ARIN | US | 16th Jan 2026 |
| 142.248.254.0/24 | 256 | ARIN | US | 10th Oct 2025 |
| 142.248.255.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 142.248.36.0/23 | 512 | ARIN | US | 12th Nov 2025 |
| 142.248.39.0/24 | 256 | ARIN | US | 17th Oct 2025 |
| 142.248.4.0/22 | 1k | ARIN | US | 10th Oct 2025 |