Canada's Postal Code System: FSA and LDU

## The Canadian Format

Canada uses a 6-character alphanumeric postal code in the format **A1A 1A1** — alternating letters and digits. This format is unique worldwide and was introduced in 1971, replacing a numeric zone system used in major cities.

## Two-Part Structure

| Part | Name | Format | Meaning |
|------|------|--------|---------|
| First 3 | Forward Sortation Area (FSA) | A1A | Province + urban/rural + geographic area |
| Last 3 | Local Delivery Unit (LDU) | 1A1 | Specific block face, building, or route |

## The First Letter

The first letter identifies the province or territory:

- **A** — Newfoundland and Labrador
- **B** — Nova Scotia
- **C** — Prince Edward Island
- **E** — New Brunswick
- **G, H, J, K, L, M, N, P** — Quebec and Ontario
- **R** — Manitoba
- **S** — Saskatchewan
- **T** — Alberta
- **V** — British Columbia
- **X** — Northwest Territories and Nunavut
- **Y** — Yukon

Letters D, F, I, O, Q, U, W, Z are not used to avoid confusion.

## Urban vs. Rural

The second character distinguishes urban from rural areas:

- **0 (zero)** → Rural FSA
- **1-9** → Urban FSA

In urban FSAs, a single LDU might cover one side of a city block. In rural FSAs, an LDU can span a large geographic area served by a single mail route.

## Comparison with US System

Canada Post manages approximately **850,000** active postal codes for a population of 40 million, compared to 41,700 US ZIP codes for 330 million people. This means Canadian postal codes are roughly **26 times more granular** on a per-capita basis.

## Santa Claus Gets His Own Code

The postal code **H0H 0H0** is reserved for letters to Santa Claus. Canada Post volunteers reply to over 1.5 million letters annually, in more than 30 languages.