Can you name all of the states in the United States? Chances are, even if you were able to name all 50 states, you likely got a few names wrong. How? Well, unless you are a history buff or have a fascination with state names, odds are you forgot to include the term commonwealth in a few of the state names. That's right — four states in the United States are actually considered commonwealths and include the term in their official name. In addition to the four states, there are two territories in the United States that are considered commonwealths – Puerto Rico and the Northern Mariana Islands. Unlike the four states listed below, these commonwealths are not official states. Let's take a look at which states have commonwealth in their name.

The Commonwealth of Pennsylvania

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Pennsylvania is one of four states that is actually a commonwealth. One of the original 13 colonies and the second state to become admitted to the union, Pennsylvania is officially known as the Commonwealth of Pennsylvania. But if you don't remember hearing about the Commonwealth of Pennsylvania in history class or remember seeing the name on a map, it's no surprise. Pennsylvania uses the term "state" and "commonwealth" pretty interchangeably.

But what does this mean? Do these states have certain laws or ordinances that apply to commonwealths? Are they actually British territories? As it turns out, no. The real answer is a little less exciting.  The only difference between a state and a commonwealth is the name. The term commonwealth has British origins and refers to the common good of the citizens. The term was first used in the late 1700s. Today, though Pennsylvania and three other states are still officially commonwealths, the only place you'll typically see the term is on official government sites or across legal documents.

If you visit the official website for the Pennsylvania government, you will see that it proudly boasts the name "The Commonwealth of Pennsylvania." But, if you scroll down to the bottom of the page and view the state seal, you will find that it reads, "Seal of the State of Pennsylvania" right above the eagle. While the term "commonwealth" was first officially used in 1776 when Pennsylvania's founders wrote the commonwealth constitution, the state has been inconsistent with the term.

The Commonwealth of Massachusetts

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That's right, the double s's and double t's aren't the only way people misspell the name of this state. According to the state's constitution, the official name is "The Commonwealth of Massachusetts." Like the Commonwealth of Pennsylvania, the Commonwealth of Massachusetts is also one of the original 13 colonies. On February 6, 1788, the Commonwealth of Massachusetts became the sixth state to be admitted to the union.

A 2018 Boston Globe article speculated that there might be a specific reason why Massachusetts chose to designate itself as a commonwealth and not a state. According to the Globe, an earlier version of the constitution actually referred to Massachusetts as, "the state of Massachusetts Bay." However, this version did not get approval from then state delegate John Adams. The Globe writes that the terms "state" once meant republic and Adams viewed the term as another term for the monarchy. The term "commonwealth" was used to ensure that Massachusetts was viewed as its own individual republic and not a part of the monarchy. Although it is most often referred to simply as Massachusetts, the Commonwealth of Massachusetts seems to be more consistent with using their formal name.

The Commonwealth of Virginia

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Virginia holds special historical significance. In addition to being one of the original 13 colonies and the 10th state to be admitted to the union, English settlers established the first English colony in Jamestown, Virginia. The state is the home to many historic sites and three of the oldest cities in the country. It is also where the American Civil War ended in 1865 and the home state of both George Washington and Thomas Jefferson. Eight U.S. presidents hail from the state (including four of the first five), which is more than any other state.

Over the years, the Commonwealth of Virginia has decreased in size. The area that is now known as the Commonwealth of Kentucky separated from the state in 1792 and West Virginia became its own state in 1863.

According to the Library of Virginia, the Commonwealth of Virginia first used the term commonwealth in 1776 when it drafted its constitution. The library notes that this distinction was likely made to emphasize the government as one based on the common good of the people.

The Commonwealth of Kentucky

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You might have noticed a theme. Up until now, all of the previous commonwealths were part of the original 13 colonies. The Commonwealth of Kentucky has the distinction of being the only commonwealth that was not an original colony. According to an Eastern Kentucky University professor, the matter of Kentucky's name comes down to basic geography. Professor Tom Appleton told WFPL, "Virginia being a commonwealth, that was just sort of our heritage."

Many people may not realize it, but at one time, Kentucky was actually a part of Virginia. During the 1700s, the area was known as Kentucky County. In 1792, the county separated from Virginia and became a state, sticking with the term "commonwealth." At that point, became the Commonwealth of Kentucky.

Pride in the commonwealth name is evident throughout the state's government. The name Commonwealth of Kentucky can be found on the state flag, its state seal, and on its official website.