Utrecht borders the Eemmeer in the north, the province of Gelderland in the east, the river Rhine in the south, the province of South Holland in the west and the province of North Holland in the northwest.
In the International Organization for Standardization world region code system Utrecht makes up one region with code -UT.
In the Middle Ages, most of the area of the current province was ruled by bishops of the Bishopric of Utrecht. The bishopric was founded in 722 by Willibrord. Many wars were fought between Utrecht and the neighbouring counties and duchies, Holland, Guelders and Brabant. In 1527, the bishop of Utrecht sold his worldly power over his territories to Emperor Charles V, who already owned most other Dutch provinces. However, the Habsburg rule did not last long, as Utrecht joined the revolt of the United Provinces against Charles's son Philip II of Spain in 1579. In World War II, Utrecht was held by German forces until the general capitulation of the Germans in the Netherlands on May 5, 1945. It was occupied by Canadian Allied forces on May 7, 1945. The towns of Oudewater, Woerden and Vianen were transferred from the province of South Holland to Utrecht in 1970, 1989 and 2002 respectively.
In February 2011, Utrecht, together with the provinces of North Holland and Flevoland, showed a desire to investigate the feasibility of a merger between the three provinces. This has been positively received by the Dutch cabinet, for the desire to create one Randstad province has already been mentioned in the coalition agreement. The province of South Holland, part of the Randstad urban area, visioned to be part of the Randstad province, and very much supportive of the idea of a merger into one province, is not named. With or without South Holland, if created, the new province would be the largest in the Netherlands in both area and population.