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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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
26,993 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 159.3.0.0/16 | 65.5k | ARIN |  US | 21st Feb 1992 |
| 159.40.0.0/16 | 65.5k | ARIN | US | 21st Feb 1992 |
| 159.42.0.0/17 | 32.8k | ARIN | US | 6th Mar 1992 |
| 159.42.128.0/17 | 32.8k | ARIN | US | 6th Mar 1992 |
| 159.43.0.0/16 | 65.5k | ARIN | US | 6th Mar 1992 |
| 159.44.0.0/16 | 65.5k | ARIN | US | 6th Mar 1992 |
| 159.5.0.0/16 | 65.5k | ARIN | US | 21st Feb 1992 |
| 159.57.0.0/16 | 65.5k | ARIN | US | 24th Mar 1992 |
| 159.59.0.0/16 | 65.5k | ARIN | US | 13th Mar 1992 |
| 159.61.0.0/18 | 16.4k | ARIN | US | 13th Mar 1992 |
| 159.61.128.0/20 | 4.1k | ARIN | US | 13th Mar 1992 |
| 159.61.144.0/21 | 2k | ARIN | US | 13th Mar 1992 |
| 159.61.156.0/22 | 1k | ARIN | US | 13th Mar 1992 |
| 159.61.160.0/19 | 8.2k | ARIN | US | 13th Mar 1992 |
| 159.61.64.0/20 | 4.1k | ARIN | US | 13th Mar 1992 |
| 159.61.81.0/24 | 256 | ARIN | US | 13th Mar 1992 |
| 159.61.82.0/23 | 512 | ARIN | US | 13th Mar 1992 |
| 159.61.84.0/22 | 1k | ARIN | US | 13th Mar 1992 |
| 159.61.88.0/21 | 2k | ARIN | US | 13th Mar 1992 |
| 159.61.96.0/19 | 8.2k | ARIN | US | 13th Mar 1992 |
| 159.67.0.0/16 | 65.5k | ARIN | US | 13th Mar 1992 |
| 159.68.0.0/16 | 65.5k | ARIN | US | 13th Mar 1992 |
| 159.70.0.0/16 | 65.5k | ARIN | US | 13th Mar 1992 |
| 159.76.0.0/16 | 65.5k | ARIN | US | 5th Mar 1992 |
| 159.78.0.0/16 | 65.5k | ARIN | US | 19th Mar 1992 |
| 159.79.0.0/16 | 65.5k | ARIN | US | 20th Mar 1992 |
| 159.88.0.0/16 | 65.5k | ARIN | US | 25th Mar 1992 |
| 159.9.0.0/16 | 65.5k | ARIN | US | 21st Feb 1992 |
| 159.97.0.0/16 | 65.5k | ARIN | US | 31st Mar 1992 |
| 16.107.0.0/16 | 65.5k | ARIN | US | 11th Jul 2022 |
| 16.109.0.0/16 | 65.5k | ARIN | US | 18th May 1989 |
| 16.110.0.0/15 | 131k | ARIN | US | 18th May 1989 |
| 16.13.0.0/16 | 65.5k | ARIN | US | 18th May 1989 |
| 16.139.0.0/16 | 65.5k | ARIN | US | 18th May 1989 |
| 16.141.0.0/16 | 65.5k | ARIN | US | 29th Sept 2023 |
| 16.149.0.0/16 | 65.5k | ARIN | US | 29th Sept 2023 |
| 16.150.0.0/15 | 131k | ARIN | US | 30th Aug 2022 |
| 16.160.0.0/15 | 131k | ARIN | US | 18th May 1989 |
| 16.167.0.0/16 | 65.5k | ARIN | US | 18th May 1989 |
| 16.175.0.0/16 | 65.5k | ARIN | US | 18th Nov 2020 |
| 16.180.0.0/15 | 131k | ARIN | US | 18th Nov 2020 |
| 16.183.0.0/16 | 65.5k | ARIN | US | 18th May 1989 |
| 16.185.0.0/16 | 65.5k | ARIN | US | 18th Nov 2020 |
| 16.186.0.0/16 | 65.5k | ARIN | US | 29th Sept 2023 |
| 16.187.0.0/16 | 65.5k | ARIN | US | 9th Feb 2022 |
| 16.188.0.0/15 | 131k | ARIN | US | 9th Feb 2022 |
| 16.193.0.0/16 | 65.5k | ARIN | US | 4th Apr 2024 |
| 16.194.0.0/15 | 131k | ARIN | US | 4th Apr 2024 |
| 16.196.0.0/14 | 262k | ARIN | US | 4th Apr 2024 |
| 16.200.0.0/15 | 131k | ARIN | US | 18th May 1989 |