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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 unannounced space registered through ARIN, largest first.
Unannounced blocks in United States
26,277 blocks match, ordered by prefix.
| Prefix | Addresses | Registry | Country | Allocated |
|---|---|---|---|---|
| 189.49.128.0/17 | 32.8k | ARIN |  US | 29th Jul 2026 |
| 189.70.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 189.72.96.0/19 | 8.2k | ARIN | US | 13th Mar 2025 |
| 189.82.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 190.2.190.0/24 | 256 | ARIN | US | 26th May 2026 |
| 191.0.0.0/18 | 16.4k | ARIN | US | 24th Jul 2026 |
| 191.0.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.2.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 191.212.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 191.216.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.218.0.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.220.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 191.40.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.44.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.45.128.0/17 | 32.8k | ARIN | US | 29th Jul 2026 |
| 191.45.64.0/18 | 16.4k | ARIN | US | 24th Apr 2026 |
| 191.46.0.0/15 | 131k | ARIN | US | 29th Jul 2026 |
| 192.100.10.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.11.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.12.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.13.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.141.0/24 | 256 | ARIN | US | 15th Apr 1991 |
| 192.100.142.0/24 | 256 | ARIN | US | 15th Apr 1991 |
| 192.100.145.0/24 | 256 | ARIN | US | 17th Apr 1991 |
| 192.100.146.0/24 | 256 | ARIN | US | 17th Apr 1991 |
| 192.100.147.0/24 | 256 | ARIN | US | 22nd Apr 1991 |
| 192.100.15.0/24 | 256 | ARIN | US | 12th Mar 1991 |
| 192.100.17.0/24 | 256 | ARIN | US | 13th Mar 1991 |
| 192.100.19.0/24 | 256 | ARIN | US | 14th Mar 1991 |
| 192.100.20.0/24 | 256 | ARIN | US | 14th Mar 1991 |
| 192.100.21.0/24 | 256 | ARIN | US | 14th Mar 1991 |
| 192.100.26.0/24 | 256 | ARIN | US | 18th Mar 1991 |
| 192.100.27.0/24 | 256 | ARIN | US | 19th Mar 1991 |
| 192.100.28.0/24 | 256 | ARIN | US | 19th Mar 1991 |
| 192.100.3.0/24 | 256 | ARIN | US | 11th Mar 1991 |
| 192.100.31.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.32.0/21 | 2k | ARIN | US | 22nd Mar 1991 |
| 192.100.40.0/22 | 1k | ARIN | US | 22nd Mar 1991 |
| 192.100.44.0/23 | 512 | ARIN | US | 22nd Mar 1991 |
| 192.100.46.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.47.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.48.0/23 | 512 | ARIN | US | 22nd Mar 1991 |
| 192.100.50.0/24 | 256 | ARIN | US | 22nd Mar 1991 |
| 192.100.56.0/24 | 256 | ARIN | US | 25th Mar 1991 |
| 192.100.57.0/24 | 256 | ARIN | US | 26th Mar 1991 |
| 192.100.58.0/24 | 256 | ARIN | US | 26th Mar 1991 |
| 192.100.62.0/24 | 256 | ARIN | US | 26th Mar 1991 |
| 192.100.67.0/24 | 256 | ARIN | US | 1st Apr 1991 |
| 192.100.69.0/24 | 256 | ARIN | US | 2nd Apr 1991 |
| 192.100.72.0/22 | 1k | ARIN | US | 28th Aug 2012 |