Travel Through This U.S. State Borders Quiz

The Toledo War was a border dispute over the land in modern-day northern Ohio. The controversy heated up as Michigan sought statehood around 1833, and even led to the mobilization of troops. In the end, Michigan ceded the Toledo Strip to Ohio in exchange for statehood plus territory in the Upper Peninsula region.

When the borders of Illinois were determined prior to its statehood, an 1817 proposal placed the northern boundary much further south than it sits today. A proposal by Nathaniel Pope, who was then secretary of the Illinois Territory, extended the lines farther north so the state could border Lake Michigan. Pope’s resolution was adopted, granting Illinois an additional area that includes modern-day Chicago.

The Treaty of Guadalupe Hidalgo marked the end of the Mexican-American War on February 2, 1848. The agreement saw Mexico cede 55% of its total land area to the United States, which included territory in California, Nevada, Utah, New Mexico, Arizona, Colorado, Oklahoma, Kansas, and Wyoming. The agreement also established the modern-day southern border of California.

Kansas is very nearly rectangular, except for the Missouri River flowing through its northeastern corner. The state, whose borders were defined during the 19th century by the Kansas-Nebraska Act, the Platte Purchase, and the Missouri Compromise, is also home to the geographic center of the contiguous United States.

Between New Hampshire and Vermont is a river named for another state: Connecticut. The border is set by the low water mark on the western side of the river — a specific distinction that the U.S. Supreme Court officially defined in 1933, after centuries of disputes over the exact location of the border.

In 1819, Secretary of State and future President John Quincy Adams negotiated the Adams-Onís Treaty with Spanish Special Envoy Luis de Onís in order to set boundaries between Spanish and U.S. claims across the continent. The 42nd parallel was one such boundary, and it remains as Nevada's northern border with Oregon and Idaho.

In 1854, six years after the end of the Mexican-American War, the United States agreed to pay $10 million for a 29,000-square-mile section of Mexico that later became part of Arizona and New Mexico. Known as the Gadsden Purchase, the deal established the southwestern border of the state of New Mexico.

At the tip of Oklahoma's panhandle lies Cimarron County, the only county in the U.S. to border four states: Kansas, Texas, New Mexico, and Colorado. Before the county’s creation in 1907, the area was part of a lawless region of the panhandle known as “No Man’s Land,” though the bandits who used to inhabit the area are long gone.

The historic Ellis Island, which welcomed millions of immigrants between 1892 and 1954, is located in both New York and New Jersey. This was determined by a 1998 U.S. Supreme Court case, which settled a longtime dispute between the two states. It determined that while the main building and museum are located in New York, the majority of the island is part of New Jersey.

West Virginia was originally part of the larger state of Virginia. During the American Civil War, 48 breakaway counties in the western part of the state sought to formally join the Union and distance themselves from Virginia’s plan to secede. The border separating West Virginia and Virginia was formally established when West Virginia was recognized as a state on June 20, 1863.

Before there was a North and South Dakota, the larger Dakota Territory encompassed the region, as well as parts of Wyoming and Montana. By the year 1868, the territory was reduced to the point that it only included the region of modern-day North and South Dakota. The borders of those two states were officially established in 1889.

In the early 1800s, a wealthy landowner named John Hardeman Walker realized that the proposed Missouri borders theoretically put him under the jurisdiction of the Arkansas government. Preferring Missouri's laws, Walker lobbied the government to include his landholdings, which later became known as the "bootheel" of Missouri.

Four U.S. states border Mexico: California, Arizona, Texas, and New Mexico. All four states were previously part of Mexico before becoming U.S. territories.

Alaska’s original boundaries were largely defined in the 1825 Treaty of St. Petersburg between Russia and Canada, before the territory was acquired by the U.S. in 1867. Shortly after the U.S. purchased the landmass, the Canadian government petitioned the U.S. to survey the Alaskan panhandle to clearly define the region’s southeastern borders. Alaska later became a U.S. state in 1959.

The state borders two Great Lakes: Lake Erie to the west and Lake Ontario to the north.

Thirteen U.S. states share a border with Canada: Maine, New Hampshire, Vermont, New York, Pennsylvania, Ohio, Michigan, Minnesota, North Dakota, Montana, Idaho, Washington, and Alaska.

South Dakota became a state in 1889 as a response to the large influx of settlers who had traveled to the Dakota territory during a gold rush in the Black Hills that began in the 1870s.

In 1821, the U.S. signed the Adams-Onis Treaty with Spain, establishing the Sabine and Red rivers as the western boundary of Louisiana.

In 1842, the Webster-Ashburton Treaty established the northeasternmost boundary of the United States, separating Maine from the British-controlled land that later became Canada. It created the modern-day demarcation between Maine and New Brunswick province to the north. Maine is the only state that borders exactly one other U.S. state: New Hampshire, which forms part of its western border.

Washington, D.C., was founded in 1790 and is bordered to the north, east, and west by Maryland and to the south by Virginia.

Florida is one of five states that border the Gulf of Mexico. The others are Texas, Louisiana, Alabama, and Mississippi.

In 1884, the U.S. and Mexico signed a treaty acknowledging the Rio Grande as the official boundary between Texas and Mexico.

When California became the 31st state in 1850, it shared its eastern border with the Nevada Territory and the New Mexico Territory. The Nevada Territory became the state of Nevada in 1864, and the portion of the New Mexico Territory bordering California became Arizona in 1912.

When Hawaii joined the union in 1949, it became the only state in the U.S. to be surrounded by water. It is bordered on all sides by the Pacific Ocean.

The Mason-Dixon Line was initially drawn to divide northern Maryland from southern Pennsylvania. The line was surveyed in the 1760s by Englishmen Charles Mason and Jeremiah Dixon to settle a dispute between the Penn and Calvert colonial families. The boundary came to serve a more political purpose leading up to the Civil War by dividing slave states from free states.