Yes — census.gov has IPv6.

Has both IPv4 (A) and IPv6 (AAAA) addresses.

This is a saved measurement from 2026-11-01 15:56 UTC. Check census.gov live now

IPv6 readiness

Website, mail and DNS all work over IPv6.

Website over IPv6 census.gov has an AAAA record and answers on it. ✓ 2610:20:2010:a05:1000:0:9481:4ba6 answers · 443	yes
www over IPv6 www.census.gov has 4 IPv6 addresses and answers on every one we tested. ✓ 2606:4700:78::90:0:181 answers · 443✓ 2606:4700:78::90:0:182 answers · 443✓ 2606:4700:78::90:0:183 answers · 443✓ 2606:4700:78::90:0:180 answers · 443	yes
Mail servers (MX) have IPv6 Every mail server has an AAAA record. mail1.census.gov ✓mail2.census.gov ✓	yes
Nameservers have IPv6 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up. ns1e.census.gov ✓ns2e.census.gov ✓	yes

HTTPS over IPv6 · not part of the grade yet
Loads over IPv6 with a valid certificate after 1 redirect: HTTP 200.

https://census.gov/ via 2610:20:2010:a05:1000:0:9481:4ba6 → 302https://www.census.gov/ via 2606:4700:78::90:0:181 → 200

works

Nothing keeping you from an A

Nothing to fix
Show it off: add the badge to your README.
[![IPv6](https://aaaa.bot/badge/census.gov.svg)](https://aaaa.bot/census.gov)

Check again

census.gov Has IPv6

A (IPv4)	148.129.75.166
AAAA (IPv6)	2610:20:2010:a05:1000:0:9481:4ba6

www.census.gov Has IPv6

A (IPv4)	172.65.90.26 172.65.90.27 172.65.90.24 172.65.90.25
AAAA (IPv6)	2606:4700:78::90:0:181 2606:4700:78::90:0:182 2606:4700:78::90:0:183 2606:4700:78::90:0:180

Browsers on dual-stack networks will usually pick IPv6 here (the "Happy Eyeballs" algorithm races both and prefers v6).

Copy the evidence — a citation-ready record of this measurement

IPv6 measurement: census.gov
Measured 2026-11-01 15:56:29 UTC by aaaa.bot (one server on Fly.io, region iad)

A (IPv4):    148.129.75.166
AAAA (IPv6): 2610:20:2010:a05:1000:0:9481:4ba6
www AAAA:    2606:4700:78::90:0:181, 2606:4700:78::90:0:182, 2606:4700:78::90:0:183, 2606:4700:78::90:0:180

Readiness grade A: Website, mail and DNS all work over IPv6.
- Website over IPv6: census.gov has an AAAA record and answers on it.
    2610:20:2010:a05:1000:0:9481:4ba6: answers (TCP 443)
- www over IPv6: www.census.gov has 4 IPv6 addresses and answers on every one we tested.
    2606:4700:78::90:0:181: answers (TCP 443)
    2606:4700:78::90:0:182: answers (TCP 443)
    2606:4700:78::90:0:183: answers (TCP 443)
    2606:4700:78::90:0:180: answers (TCP 443)
- Mail servers (MX) have IPv6: Every mail server has an AAAA record.
- Nameservers have IPv6: 2 of 2 nameservers checked have an AAAA record, so IPv6-only resolvers can look the domain up.

Reachability = a TCP connection opened on port 443 (or 80).

HTTPS over IPv6 (not graded): Loads over IPv6 with a valid certificate after 1 redirect: HTTP 200.
    https://census.gov/ via 2610:20:2010:a05:1000:0:9481:4ba6 -> HTTP 302, certificate: valid
    https://www.census.gov/ via 2606:4700:78::90:0:181 -> HTTP 200, certificate: valid
DNS answers via DNS-over-HTTPS (Cloudflare). Method: https://aaaa.bot/method
Permanent link: https://aaaa.bot/r/krr1VtEvgj

Permanent link: aaaa.bot/r/krr1VtEvgj · How we measure

Checked 2026-11-01 15:56:29 UTC. Full DNS report: dns.pizza/domain/census.gov · JSON: /api/v1/census.gov