H.O, S.O and B.O: Types of Post Offices in India Explained

When you look up a PIN code on PinCodeFinder, you will see every post office labelled as H.O, S.O, or B.O. These are not random abbreviations — they describe the rank and role of the post office within India's three-tier postal hierarchy.

Head Office (H.O)

A Head Office is the primary post office for a postal division. Every district typically has one Head Office, usually located in the district headquarters town. Head Offices are characterised by:

• The largest staff strength among post offices in the division
• A Treasury — they hold and manage cash for all sub-offices and branch offices under them
• Responsibility for generating account books and mail lists for the entire division
• Handling foreign mail, speed post, and registered article processing for the region
• Usually open 6 days a week with full banking and postal services

Examples: Agra Head Office (282001), Jaipur Head Office (302001), Chennai GPO (600001).

The Head Office of a state is often called the General Post Office (GPO) — for example, Mumbai GPO (400001) or Delhi GPO (110006).

Sub Office (S.O)

A Sub Office reports directly to the Head Office of its division. Sub Offices are typically located in:

• Large towns and tehsil headquarters
• Urban and semi-urban localities with significant population
• Areas that need more than a branch office but don't qualify for a full Head Office

Sub Offices offer most of the services available at a Head Office — savings accounts, speed post, registered mail, money orders, and government scheme enrolments — but they do not hold an independent treasury. They receive cash advances from the Head Office and remit accounts daily or weekly.

A single Head Office may oversee anywhere from a dozen to over a hundred sub-offices depending on the size of the division.

Branch Office (B.O)

A Branch Office is the smallest unit in the India Post hierarchy and typically serves rural villages and remote localities. Branch Offices are often run by a single Gramin Dak Sevak (GDS) — a part-time government appointee who may also be a local resident.

Key characteristics of Branch Offices:

• Limited service hours (often 4–5 hours per day)
• Basic services only: letters, parcels, money orders, small savings deposits
• May not offer speed post booking or banking services
• Report to a Sub Office (or directly to a Head Office in smaller divisions)
• Often share a PIN code with the parent Sub Office

Branch Offices are crucial for rural connectivity. India has over 1.3 lakh Branch Offices — they form the last mile of postal delivery for hundreds of millions of people in villages.

The Hierarchy in Practice

Mail flows through the hierarchy like this:

1. A letter posted at a Branch Office is collected by the GDS
2. It travels to the parent Sub Office on a mail beat
3. The Sub Office sends it to the Head Office for sorting
4. The Head Office dispatches it to the destination Head Office via Railway Mail Service or air mail
5. It flows back down: Head Office → Sub Office → Branch Office → recipient

Delivery Status: Delivery vs Non-Delivery

Within each office type, India Post also flags whether an office provides door-step delivery:

• Delivery — postmen from this office make home deliveries in their beat area
• Non-Delivery — the office does not have delivery postmen; mail must be collected at the counter

Non-delivery offices are common at transit sorting facilities, railway mail offices, and some administrative head offices that don't directly handle street delivery.