Top Sites>eCFR.io | Electronic Code of Federal Regulations (eCFR) Search & Browse

User-agent: *
Allow: /
Disallow: /on/
Disallow: /__coverage/
Disallow: /__open-version

Sitemap: https://ecfr.io/sitemap.xml

# eCFR.io

Canonical host: https://ecfr.io
Purpose: public reading, navigation, and citation interface for the Code of Federal Regulations.

## Current corpus
- Home and title browse routes under https://ecfr.io/Title-1 and similar canonical current paths.
- Current document pages are the primary canonical pages for indexing and citation.
- Search is available at https://ecfr.io/search for current-corpus discovery.

## Informational pages
- About: https://ecfr.io/about
- FAQ: https://ecfr.io/faq
- Contact: https://ecfr.io/contact
- Privacy policy: https://ecfr.io/privacy-policy

## Historical editions
- Dated routes under https://ecfr.io/on/YYYY-MM-DD/... are browsable historical pages.
- Historical /on/ routes are non-canonical and explicitly non-indexable.
- Use canonical current routes for primary discovery and sitemap traversal.

## Discovery
- Sitemap index: https://ecfr.io/sitemap.xml
- OpenSearch description: https://ecfr.io/opensearch.xml

## Usage guidance
- Prefer canonical current routes for linking and summarization.
- Treat dated /on/ routes as historical snapshots rather than primary entrypoints.
- Use page-level citations and breadcrumbs to understand CFR hierarchy and context.