Microsoft 365 US Government mailbox provider
According to Live Direct Marketing's daily Tranco top-1M scan (September 24, 2026), Microsoft 365 US Government is the mailbox provider for 277 domains — 0.04% of 675,489 domains with MX records. Detection method: primary MX record (lowest preference).
Key facts
- 277 domains in the Tranco top-1M use Microsoft 365 US Government (0.04% of domains with MX records).
- Snapshot date: 2026-09-24 — recomputed every day.
- Strongest TLD: .com (88.1% of its domains).
- Region skew: Global / US-skewed.
- Most co-used service: Microsoft 365 US Gov.
- Directory category: mailbox provider.
Why Microsoft 365 US Government appears in this category
Exchange Online for US government tenants using the office365.us sovereign-cloud namespace.
We classify it as a mailbox provider from primary MX record (lowest preference) matching a maintained provider rule. This is infrastructure attribution from public DNS, not evidence of a direct contract or exclusive use.
What the data shows
92.8% of its domains sit outside the top 100,000 — a long-tail footprint spread across smaller sites. Its single largest TLD is .com at 88.1% of its domains — a strong concentration across 12 TLDs overall. The service most often seen alongside it is Microsoft 365 US Gov (ESP), on 94.9% of its domains.
Where Microsoft 365 US Government sits in the Tranco ranking
| Tranco rank band | Domains | Share of its base |
|---|---|---|
| Top 1,000 | 0 | 0.0% |
| Top 10,000 | 2 | 0.7% |
| Top 100,000 | 15 | 5.4% |
| Top 1,000,000 | 257 | 92.8% |
| Unranked | 3 | 1.1% |
Top-level domain split
| TLD | Domains | Share | |
|---|---|---|---|
| .com | 244 | 88.1% | |
| .us | 7 | 2.5% | |
| .org | 7 | 2.5% | |
| .gov | 6 | 2.2% | |
| .mil | 5 | 1.8% | |
| .space | 2 | 0.7% | |
| .net | 1 | 0.4% | |
| .cloud | 1 | 0.4% | |
| .io | 1 | 0.4% | |
| .dev | 1 | 0.4% |
What Microsoft 365 US Government users also use
Cross-tabulated from the same daily snapshot — the other email services seen on the same 277 domains.
| Type | Service | Domains | Share of Microsoft 365 US Government users |
|---|---|---|---|
| ESP | Microsoft 365 US Gov | 263 | 94.9% |
| ESP | Salesforce | 19 | 6.9% |
| ESP | Amazon SES | 17 | 6.1% |
| ESP | Mailgun | 11 | 4.0% |
| ESP | Mailchimp | 7 | 2.5% |
| ESP | HubSpot | 7 | 2.5% |
| ESP | SendGrid (Twilio) | 6 | 2.2% |
| ESP | Zendesk | 5 | 1.8% |
| ESP | Mandrill | 4 | 1.4% |
| ESP | Proofpoint | 3 | 1.1% |
See the full Microsoft 365 US Government data page (KPI cards, trend, sample domains) →
Run a free inbox-placement test across Gmail, Outlook, Yahoo and more — see exactly where your mail lands and why.
Frequently asked questions
How many domains use Microsoft 365 US Government?
277 domains in the Tranco top-1M use Microsoft 365 US Government as their mailbox provider as of September 24, 2026 (0.04% of domains with MX records), according to Live Direct Marketing's daily DNS scan.
Is Microsoft 365 US Government common enough to affect email deliverability testing?
Microsoft 365 US Government accounts for 0.04% of domains with MX records in the top 1M. Whether you should seed a test mailbox there depends on how much of your audience it represents — the co-usage table above shows the services it appears alongside most.
Which countries or TLDs use Microsoft 365 US Government most?
Microsoft 365 US Government's largest TLD is .com (88.1% of its domains); it appears across 12 TLDs in total.