If you live in Bolivia and are an American citizen then you will find the US Embassy in Bolivia located in La Paz. There are a number of offices in Bolivia to assist Americans abroad and expats living in Bolivia. You can contact the US Embassy about a visa to the US or also for consular assistance.
US Embassy in Bolivia
Note that there are a number of offices in Bolivia to assist you. These offices are located in La Paz, Cochabamba and Santa Cruz. We have listed them below. note that the US Embassy in La Paz is around the corner from the British Embassy in Bolivia in the event you get lost.
If you require a freedom to marry letter then this can be applied for in the country. You will need this to be issued in the country by the Embassy in order to get married in the country. This normally takes a few days after applicati9n. They will then issue this and it will need to be translated and then used in Bolivia to register your marriage. You can then apply for a K3 visa or a CR1 visa for the US after this.
If you have lost your passport it needs to be reported to the local police. They will give you a cse number and the Embassy will require this number. You can then apply for a new US passport. This can be an emergency travel document or an actual US passport. You will need to call them first in order to normally book and appointment.
Registering a birth is the same. Take all the local documents and have these translated into English and certified. Photos will be needed and all the parties with their ID cards or passports have to go together to the Embassy for this registration process. You can then register your American child born abroad. See the topic called Register a Birth Abroad on here as well for some more insight.
Details for US Embassy in Bolivia
Address: Avenida Arce #2780, La Paz, Bolivia.
Phone:  (591-2) 216-8000.
Fax:  (591-2) 216-8111
Santa Cruz Consular Agency Contact Information
Edificio Centro Empresarial Equipetrol, 4th Floor
Intesection of Av. San Martin and Av. Las Ramblas
Equipetrol Norte, Santa Cruz, Bolivia
Phone:  (591-2) 2-216-8000
There are a number of US Embassies around the world. See the US Embassy in the United Kingdom as well as the US Embassy in Saudi Arabia. There is also a note on USCIS on this website.