In many counties across the US, this government office is typically referred to the "recorder of deeds". Its function is to maintain public records and documents, including records related to parcels of land and about any rights or restrictions on those land parcels. Given that this office keeps records of matters well beyond just real estate matters, it would not be a very close translation of a Grundbuchamt. At best, it might be used as a parenthetical with the phrase "similar to a registry or recorder of deeds in the United States".
There are multiple definitions - click on the translation that matches your context.
the system of recording title to land; the government office charged with administering that system
After the closing, the buyer's attorney stopped by the Registry of Deeds to ensure that the change of ownership was duly recorded.