https://support.squarespace.com/hc/en-us/articles/206540947-Setting-up-taxes-in-Squarespace-Commerce

Squarespace forum posts seem to confirm:

https://forum.squarespace.com/topic/151517-squarespace-sales-tax-issues/?tab=comments#comment-332158

https://forum.squarespace.com/topic/151482-sales-tax/?tab=comments#comment-332046

And elsewhere:

https://www.reddit.com/r/squarespace/comments/8wmulh/how_to_configure_sales_tax_in_the_us_after_the/?utm_source=amp&utm_medium=&utm_content=post_body https://accountingforjewelers.com/sales-tax-ca-squarespace/ https://www.printful.com/faq/taxes-and-billing/sales-tax/374-how-do-i-configure-my-ecommerce-platform-to-charge-the-correct-tax-rate-