As of July 1635, there were eleven established provinces in the United States of Europe. The heads of state of each of those provinces, whether elected or appointed by the emperor or established by traditional custom, sat in the USE's upper house, the House of Lords. ("The Senate," in the stubborn parlance of the CoCs.) As such, all eleven of them added the official rank of senator to whatever other posts and positions and titles they held.
Those eleven provinces were:
Magdeburg, which was the name of the province as well as the capital city. The province's head of state was an elected governor.
The State of Thuringia-Franconia, whose capital had formerly been Grantville and was now Bamberg. Like Magdeburg, this state elected its own governor, although the title of the post—president—remained that of its predecessor, the New United States.
Those were the only two provinces that had a fully republican structure and elected their own heads of state. Not coincidentally, they were the strongholds of the Fourth of July Party and the Committees of Correspondence.
There were three provinces whose heads of state, while not elected, were established by the provinces themselves. Like Magdeburg and the SoTF, these provinces were entirely self-governing within the overall federal structure and laws of the USE. They were no longer, or had never been, under direct imperial administration.
They were:
Hesse-Kassel, still governed by its traditional ruler, Landgrave Wilhelm V. The Landgrave, along with his wife Amalie Elizabeth, were prominent leaders of the moderate wing of the Crown Loyalist Party that now controlled the USE Parliament and whose leader, Wilhelm Wettin, was the newly elected prime minister.
Brunswick was also governed by its traditional ruler, Duke George of Brunswick-Lüneburg. However, since the duke was now serving as the commander of the USE army's Second Division and was marching this very moment into Saxony, the province was being managed by one of his subordinates, Loring Schultz.
Most recently, the Tyrol had voluntarily joined the United States of Europe. The agreement made between the Tyrol's regent Claudia de Medici and the USE's envoy Philipp Sattler was that a regency council would be set up under Dr. Wilhelm Bienner, the chancellor of Tyrol, for Claudia's two minor sons. Under the new constitution of the province, they and their heirs would be "hereditary governors."
Four provinces had heads of state who had been appointed by Emperor Gustav II Adolf. However, they were no longer under direct imperial administration and were at least technically self-governing:
Westphalia, whose administrator was Prince Frederik of Denmark. He'd been appointed in June of 1634 as a result of the Congress of Copenhagen. They were still wrangling over the title. Frederik wanted "Prince of Westphalia" but the emperor was reluctant to agree and preferred "Governor." Gustav Adolf would probably give in eventually, though, since his misgivings were general in nature whereas the Danes—both Frederik and his father Christian IV, the king of Denmark—were quite keen on the matter.
The Province of the Upper Rhine, whose administrator was Wilhelm Ludwig of Nassau-Saarbrücken. He'd also been appointed in June of 1634 during the proceedings at Copenhagen. Wilhelm Ludwig, not of royal birth, had been happy enough to settle for the title of governor. His position as the Upper Rhine's head of state was something of a formality, anyway, since he was spending most of his time assisting his father-in-law in Swabia. The actual management of the province was in the hands of his deputy, Johann Moritz of Nassau-Siegen.
The "self-governing" aspect of the remaining two provinces in this category was questionable, since their official head of state was the emperor himself. Gustav II Adolf, never loath to use medieval precedents, had cheerfully appointed himself the duke of both Mecklenburg and Pomerania.
The provincial independence of Pomerania was pretty much a myth. For all practical purposes, Pomerania was still being ruled by direct imperial fiat. True, Pomeranians did elect members to Parliament. But all of them were vetted by the Swedish chancellor, Axel Oxenstierna. Insofar as the province had any independent politics at all, it tended to be a bastion of the reactionary wing of the Crown Loyalists.
Mecklenburg was quite different. That province had been transformed in the course of the civil war which had taken place there following the Dreeson Incident. With a handful of exceptions, the nobility had fled the province. The Committees of Correspondence were now as dominant on the ground as they were in Magdeburg and the State of Thuringia-Franconia.
A couple of provinces were "self-governing" in the sense that they could elect representatives to Parliament: the Province of the Main and the Oberpfalz. But their heads of state of state were still appointees of the emperor and answered to him directly. The administrator of the Province of the Main was the Swedish general Nils Abrahamsson Brahe. The administrator of the Oberpfalz was the new prime minister's younger brother, Ernst Wettin.