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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,963 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 146.180.0.0/16 | 65.5k | ARIN |  US | 26th Feb 1991 |
| 146.19.181.0/24 | 256 | RIPE NCC | US | 17th Nov 2021 |
| 146.19.252.0/24 | 256 | RIPE NCC | US | 22nd Nov 2021 |
| 146.196.100.0/22 | 1k | APNIC | US | 22nd Mar 2016 |
| 146.204.0.0/15 | 131k | ARIN | US | 28th Feb 1991 |
| 146.208.0.0/16 | 65.5k | ARIN | US | 2nd Dec 1994 |
| 146.223.0.0/16 | 65.5k | ARIN | US | 24th Aug 1994 |
| 146.237.0.0/16 | 65.5k | ARIN | US | 5th Mar 1991 |
| 146.238.0.0/16 | 65.5k | ARIN | US | 5th Mar 1991 |
| 146.239.0.0/16 | 65.5k | ARIN | US | 5th Mar 1991 |
| 146.24.0.0/13 | 524k | ARIN | US | 18th Jan 1991 |
| 146.252.0.0/16 | 65.5k | ARIN | US | 6th Mar 1991 |
| 146.255.184.0/24 | 256 | RIPE NCC | US | 30th Aug 2021 |
| 146.32.0.0/13 | 524k | ARIN | US | 18th Jan 1991 |
| 146.40.0.0/14 | 262k | ARIN | US | 18th Jan 1991 |
| 146.44.0.0/15 | 131k | ARIN | US | 18th Jan 1991 |
| 146.46.0.0/16 | 65.5k | ARIN | US | 18th Jan 1991 |
| 146.47.0.0/16 | 65.5k | ARIN | US | 18th Jan 1991 |
| 146.61.0.0/16 | 65.5k | ARIN | US | 21st Jan 1991 |
| 146.69.0.0/16 | 65.5k | ARIN | US | 23rd Jan 1991 |
| 146.71.128.0/17 | 32.8k | ARIN | US | 23rd Jan 1991 |
| 146.73.0.0/16 | 65.5k | ARIN | US | 23rd Jan 1991 |
| 146.84.0.0/17 | 32.8k | ARIN | US | 28th Jan 1991 |
| 146.84.128.0/17 | 32.8k | ARIN | US | 28th Jan 1991 |
| 146.88.148.0/24 | 256 | ARIN | US | 3rd Sept 2015 |
| 146.89.0.0/16 | 65.5k | ARIN | US | 2nd Apr 1996 |
| 146.94.128.0/18 | 16.4k | ARIN | US | 15th Sept 2026 |
| 146.94.240.0/20 | 4.1k | ARIN | US | 29th Jan 1991 |
| 147.101.0.0/16 | 65.5k | ARIN | US | 11th Mar 1991 |
| 147.107.0.0/16 | 65.5k | ARIN | US | 14th Mar 1991 |
| 147.113.0.0/16 | 65.5k | ARIN | US | 19th Mar 1991 |
| 147.121.0.0/16 | 65.5k | ARIN | US | 26th Mar 1991 |
| 147.141.0.0/16 | 65.5k | ARIN | US | 22nd Mar 1991 |
| 147.160.150.0/23 | 512 | ARIN | US | 30th May 2019 |
| 147.160.152.0/23 | 512 | ARIN | US | 17th May 2019 |
| 147.160.16.0/21 | 2k | ARIN | US | 15th Aug 2019 |
| 147.160.7.0/24 | 256 | ARIN | US | 24th Jul 2019 |
| 147.170.0.0/16 | 65.5k | ARIN | US | 20th Jun 1991 |
| 147.179.0.0/16 | 65.5k | ARIN | US | 5th Jul 1991 |
| 147.185.0.0/20 | 4.1k | ARIN | US | 5th Jul 1991 |
| 147.185.108.0/22 | 1k | ARIN | US | 5th Jul 1991 |
| 147.185.128.0/23 | 512 | ARIN | US | 5th Jul 1991 |
| 147.185.140.0/22 | 1k | ARIN | US | 5th Jul 1991 |
| 147.185.168.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 147.185.173.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 147.185.174.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 147.185.179.0/24 | 256 | ARIN | US | 5th Jul 1991 |
| 147.185.18.0/23 | 512 | ARIN | US | 5th Jul 1991 |
| 147.185.180.0/22 | 1k | ARIN | US | 5th Jul 1991 |
| 147.185.190.0/24 | 256 | ARIN | US | 27th Oct 2021 |