Do you always put a comma between town and state?

You don't *always* put a comma between a town and state. The rule depends on whether you're using the town and state as part of a complete sentence:

* When used as part of a complete sentence: Yes, you put a comma between the town and state.

* Example: "I grew up in Seattle, Washington."

* When used as a simple address: No, you don't use a comma.

* Example: "My address is 123 Main Street, Seattle Washington."

Let me know if you'd like more examples!