According to the Law on the Register of Natural Persons Law you have an obligation to notify the Office of Citizenship and Migration Affairs of your and your children’s address of residence abroad if residing there exceeds three months. It is also necessary to notify within 30 days if the address of foreign residence is changed.
This can be done via portal www.latvija.lv or by sending an application by mail directly to the Personal Status Control Division of the Office of Citizenship and Migration Affairs. More detailed information about the notification of the address of the place of residence in the USA can be found here
The notification of the address of the place of residence in the USA submitted in person at the Embassy.
If notification of your address is not done while receiving another consular service, you must make the payment in the amount of 50 USD .