Which of the following is NOT a principal state institution mentioned in the Constitution?

The reason that the Wyoming State Prison in Rawlins is identified as not being a principal state institution mentioned in the Constitution is that the Wyoming Constitution primarily outlines the framework and functions of government, including the legislative, executive, and judicial branches, as well as the rights of citizens and the operation of state institutions that serve specific governmental or educational roles.

While the University of Wyoming, as a public university, plays a significant role in the education system and is established as a state institution under the Constitution, and similarly, the Capitol in Cheyenne is the seat of government, the State Hospital is explicitly named for its role in health and mental health services. The prison, while certainly a significant institution within the state's correctional system, does not fall into the category of those principal institutions the Constitution emphasizes, which focus more on governance and institutional education rather than correctional facilities.

The other options represent key institutions that function directly within the educational and governmental structure recognized by the Wyoming Constitution, reflecting its foundational priorities.