If you need to restrict your shipping to a radius around a specific point or address, for example 10 miles around your warehouse, you can use some free tools to generate the zip/post code lists for that radius and paste them into the Better Shipping app.
Note, the links below use the same instructions. Please see the screenshots below to add the zip/post codes to the Better Shipping app. Once you have your list if you open the Better Shipping app from your Shopify admin, or go here: https://bettershipping.herokuapp.com/, you can paste in your copied zip codes/postcodes.
We also have a blog article with an informal video how to set up an zip code shipping rate here: Restrict Your Store Using Zip Codes
USA Zip Code Radius:
Canadian Postal Code Radius:
UK Postcode Radius:
Australian Postcode Radius:
You can adjust the settings to suit your needs: