With Google Domains transferring all of their domains to Squarespace, a lot of people need to know how to point their root domains to their Heroku apps.

First, as explained in the Heroku docs, add your root domain:

$ heroku domains:add example.com -a example-app
Adding example.com to ⬢ example-app... done
▸    Configure your app's DNS provider to point to the DNS Target
▸    whispering-willow-5678.herokudns.com.
▸    For help, see https://devcenter.heroku.com/articles/custom-domains

The domain example.com has been enqueued for addition
▸    Run heroku domains:wait 'example.com' to wait for completion

Take note of the DNS target. Here, it’s “whispering-willow-5678.herokudns.com”, but for you it will be different.

Then, in Squarespace, under Domains → example.com → DNS → DNS Settings, add a custom record. Set the host to ‘@’ (without quotes), the type to ‘ALIAS’, and the data to the DNS target Heroku gave you. Note that a CNAME record will not work for root domains.

After a few minutes, your root domain should point to your Heroku app.