Obtaining A Copy Of A Lost Birth Certificate

[dbhuphaibool]

I am currently living in Argentina and am trying to get a student visa here. I was born in Thailand and although am a US citizen, the Argentine Immigration requires that I present a birth certificate to apply for a student visa here in Argentina. From reading various posts, it seems that the local district (amphur?) of where I was born would have my birth certificate information. My quesiton is how do I locate this office and contact them to ask them questions?

I was born in Ramathibodi Hospital (270 Rama 6 street) in Phayathai district. Does anyone know which local district office would correspond to this hospital and how to obtain the district office's contact information (phone number & address, etc)?

Also, a family member will be travelling to Thailand in the coming month but only staying for a short time. I wanted to contact them to see how long it would roughly take to get the birth certificate and what information needs to be in the letter of authorization for the family member who is requesting my birth certificate for me.

Any help would be greatly appreciated! Thanks!