In Ahrens v. Clark, 335 U.S. 188 (1948), 120 German nationals confined at Ellis Island, New York, pending deportation sought habeas corpus on the principal ground that the removal orders exceeded the President's statutory authority under the Alien Enemy Act of 1798. They filed their petitions in the District Court for the District of Columbia, naming as respondent the Attorney General of the United States. Construing the statutory predecessor to 2241 (a), we held that the phrase, "within their respective jurisdictions," precluded the District Court for the District of Columbia from inquiring into the validity of the prisoners' detention at Ellis Island, and we therefore affirmed the dismissal of the petitions on jurisdictional grounds. The Supreme Court's decision in Ahrens rested on the view that Congress' paramount concern was the risk and expense attendant to the "production of prisoners from remote sections, perhaps thousands of miles from the District Court that issued the writ. The opportunities for escape afforded by travel, the cost of transportation, the administrative burden of such an undertaking negate such a purpose." (335 U. S., at 191.) In Ahrens, the Court held that "the presence within the territorial jurisdiction of the District Court of the person detained is a prerequisite to filing a petition for writ of habeas corpus." 335 U. S., at 189. The Court construed the phrase "within their respective jurisdictions" to mean that Congress intended to limit the jurisdiction of a district court to prisoners in custody within its territorial jurisdiction. Id., at 193.