What visa do USA citizens receive upon arriving in Thailand and how can they extend it?

USA citizens arriving in Thailand without a visa receive a 60-day visa exemption upon entry. This exemption can be extended for an additional 30 days at any local immigration office for 1,900 baht. There are over 80 immigration offices throughout Thailand, and the extension process typically involves filing a TM30 notice if staying in accommodation served by a hotel or homeowner.