Not appealable. The Second Circuit, in Cruz v. Ridge, has held that an order of a district court transferring a case to the Second Circuit was not appealable because the plaintiff can challenge jurisdiction before the Second Circuit. The case involves an attempt by an illegal alien to challenge an immigration order by bring a habeas corpus action. The government moved to transfer to the Second Circuit because the courts of appeal have sole jurisdiction over appeals of immigration orders, which motion was granted by the district court. Cruz sought to appeal from that order. The decision in the case can be found here.