Google had made a bid to quash a warrant that was issued last year, seeking access to these emails.
In February, the search giant had been told that copying email from a server based outside the US, so that FBI agents would be able to see them as part of an investigation into a case of domestic fraud, could not be considered a seizure.
At this hearing, Google and the US government were both told by US Magistrate Judge Thomas Rueter that they would have to submit "a joint stipulation of undisputed facts relevant to the extraterritoriality analysis".
Last year, Microsoft won the right to refuse federal authorities access to customer emails stored in Ireland that were sought in connection with a drug-trafficking case.
On Wednesday, US Magistrate Judge Laurel Beeler concluded (link from The Register): "The court denies Google's motion to quash the warrant for content that it stores outside the United States and orders it to produce all content responsive to the search warrant that is retrievable in the United States, regardless of the data's actual location.
The court took into account the mechanics of the Microsoft case, but said that it agreed with the argument of the judges who dissented when the government appealed the initial decision in favour of Microsoft.
"The service provider — Google — is in the district and is subject to the court’s jurisdiction; the warrant is directed to it in the only place where it can access and deliver the information that the government seeks," the court statement read.
It quoted from one of the dissenting opinions in the Microsoft appeal: “[I]f statutory and constitutional standards are met, it should not matter” where a service provider chooses to store the 1s and 0s."
And it added: "That conclusion is especially true here. Unlike Microsoft, where storage of information was tethered to a user’s reported location... there is no storage decision here. The process of distributing information is automatic, via an algorithm, and in aid of network efficiency. In sum, the disclosure is a domestic application of the SCA (Stored Communications Act)."