# AWS Regions and Availability Zones

> AWS Regions are separate geographic areas, each made of several isolated Availability Zones. Choose them for latency, compliance, price and resilience.

- Source: https://www.itwonderlab.com/aws-regions-availability-zones/
- Published: 2026-10-05
- Updated: 2026-10-05
- Author: Javier Ruiz Jiménez (https://www.javierruizjimenez.com/)
- Site: IT Wonder Lab (https://www.itwonderlab.com/)

---

The AWS global infrastructure is organized in **Regions** and **Availability Zones**.

### Region

A **Region** is a separate geographic area, such as `us-east-1` (N. Virginia), `eu-west-1` (Ireland) or `ap-southeast-1` (Singapore). Regions are independent: resources, [VPCs](https://www.itwonderlab.com/aws-vpc/), prices and the available services are specific to each Region, and data does not leave a Region unless you move it.

Criteria to choose a Region:

- **Latency**: close to your users.
- **Compliance and data residency**: where the data must legally stay.
- **Service availability**: new services usually launch in a few Regions first.
- **Price**: it varies between Regions.

Some Regions (for example, the newest ones) have to be enabled in the account before use.

### Availability Zone (AZ)

An **Availability Zone** is one or more data centers in a Region with independent power, cooling and networking, connected to the other zones of the Region by fast, low-latency links. Zones are named with a letter (`us-east-1a`, `us-east-1b`...). Those names are mapped to physical zones differently for each AWS account; the **AZ ID** (for example `use1-az1`) identifies the same zone for all of them.

A [subnet](https://www.itwonderlab.com/aws-subnets/) lives in a single Availability Zone. To survive the failure of a data center, spread the [EC2](https://www.itwonderlab.com/aws-ec2/) instances, [load balancers](https://www.itwonderlab.com/aws-elastic-load-balancing/), [NAT Gateways](https://www.itwonderlab.com/aws-nat-gateway/) and [databases](https://www.itwonderlab.com/aws-rds/) (Multi-AZ) across at least two zones.

### Other locations

- **Edge locations** serve content and DNS for [CloudFront](https://www.itwonderlab.com/amazon-cloudfront/) and [Route 53](https://www.itwonderlab.com/aws-route-53/).
- **Local Zones** and **Wavelength Zones** bring services closer to large cities or 5G networks.

### With Terraform

The Region is set in the `provider "aws"` block (or with the `AWS_REGION` variable) and the available zones can be read with the `aws_availability_zones` data source:

```hcl
data "aws_availability_zones" "available" {
  state = "available"
}

# data.aws_availability_zones.available.names[0] -> "us-east-1a"
```

See tutorials:

-   [AWS with Terraform: The Essential Guide (2/21) – AWS Basics](https://www.itwonderlab.com/aws-terraform-tutorial-aws-basics/)
-   [AWS with Terraform: The Essential Guide (5/21) – AWS Subnets](https://www.itwonderlab.com/aws-terraform-tutorial-aws-subnets/)