Where can I extend my 30-day visa in Chiang Mai for an additional 30 days for Canadian and American passport holders?

In Chiang Mai, both Canadian and American passport holders can extend their 30-day visa at the same places: the immigration office near the airport or the office at Central Festival mall. Note that if you entered Thailand without a visa and received a 30-day stamp, this is classified as a visa exemption, not a visa. To complete the extension process, you will need to provide a TM30 form from your place of accommodation.