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It is also a snapshot, not a history: a block announced yesterday and withdrawn this morning appears here today.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 |
|---|---|---|---|---|
| 161.199.44.0/22 | 1k | ARIN |  US | 29th Jan 1993 |
| 161.199.48.0/22 | 1k | ARIN | US | 29th Jan 1993 |
| 161.199.52.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.55.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.64.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.66.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.68.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.70.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.72.0/22 | 1k | ARIN | US | 29th Jan 1993 |
| 161.199.8.0/23 | 512 | ARIN | US | 29th Jan 1993 |
| 161.199.84.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.87.0/24 | 256 | ARIN | US | 13th Aug 2019 |
| 161.199.91.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.92.0/23 | 512 | ARIN | US | 7th Jun 2019 |
| 161.199.94.0/24 | 256 | ARIN | US | 29th Jan 1993 |
| 161.199.96.0/21 | 2k | ARIN | US | 29th Jan 1993 |
| 161.201.0.0/16 | 65.5k | ARIN | US | 29th Jan 1993 |
| 161.204.0.0/16 | 65.5k | ARIN | US | 9th Feb 1993 |
| 161.210.100.0/22 | 1k | ARIN | US | 13th Jan 2026 |
| 161.210.104.0/22 | 1k | ARIN | US | 15th May 2026 |
| 161.210.112.0/20 | 4.1k | ARIN | US | 18th Feb 1993 |
| 161.210.16.0/20 | 4.1k | ARIN | US | 18th Feb 1993 |
| 161.210.160.0/20 | 4.1k | ARIN | US | 18th Feb 1993 |
| 161.210.176.0/21 | 2k | ARIN | US | 18th Feb 1993 |
| 161.210.184.0/22 | 1k | ARIN | US | 18th Feb 1993 |
| 161.210.190.0/23 | 512 | ARIN | US | 18th Feb 1993 |
| 161.210.2.0/23 | 512 | ARIN | US | 18th Feb 1993 |
| 161.210.32.0/21 | 2k | ARIN | US | 18th Feb 1993 |
| 161.210.40.0/22 | 1k | ARIN | US | 18th Feb 1993 |
| 161.210.44.0/23 | 512 | ARIN | US | 18th Feb 1993 |
| 161.210.46.0/24 | 256 | ARIN | US | 13th Jan 2026 |
| 161.210.48.0/20 | 4.1k | ARIN | US | 18th Feb 1993 |
| 161.210.64.0/20 | 4.1k | ARIN | US | 18th Feb 1993 |
| 161.210.8.0/21 | 2k | ARIN | US | 18th Feb 1993 |
| 161.210.80.0/21 | 2k | ARIN | US | 18th Feb 1993 |
| 161.210.88.0/23 | 512 | ARIN | US | 18th Feb 1993 |
| 161.210.90.0/24 | 256 | ARIN | US | 18th Feb 2026 |
| 161.211.0.0/16 | 65.5k | ARIN | US | 18th Feb 1993 |
| 161.219.0.0/16 | 65.5k | ARIN | US | 1st Mar 1993 |
| 161.233.0.0/16 | 65.5k | ARIN | US | 22nd Mar 1993 |
| 161.236.0.0/16 | 65.5k | ARIN | US | 23rd Mar 1993 |
| 161.237.0.0/16 | 65.5k | ARIN | US | 23rd Mar 1993 |
| 161.240.0.0/16 | 65.5k | ARIN | US | 27th Mar 1993 |
| 161.244.0.0/16 | 65.5k | ARIN | US | 30th Mar 1993 |
| 161.245.0.0/16 | 65.5k | ARIN | US | 30th Mar 1993 |
| 161.26.0.0/16 | 65.5k | ARIN | US | 4th Mar 2015 |
| 161.32.32.0/19 | 8.2k | ARIN | US | 14th Jun 2019 |
| 161.36.0.0/18 | 16.4k | ARIN | US | 14th May 1992 |
| 161.36.120.0/21 | 2k | ARIN | US | 14th May 1992 |
| 161.36.128.0/17 | 32.8k | ARIN | US | 14th May 1992 |