Southwest No. 7 Boundary Marker of the Original District of Columbia

Arlington County, VA has a rich and diverse history that dates back thousands of years. The area was originally inhabited by Native American tribes, including the Powhatan and the Chesapeake peoples, who lived along the banks of the Potomac River. European exploration of the region began in the early 17th century, with Captain John Smith and others making contact with the local tribes.

In 1801, the federal government acquired land along the Potomac River to establish the District of Columbia, including what is now Arlington County. However, in 1846, the portion of the land on the Virginia side of the river was retroceded back to Virginia due to political tensions between the southern states and the federal government.

During the American Civil War, Arlington County played a significant role. The area was turned into a military encampment and eventually became the site of Arlington National Cemetery, where Union soldiers were buried. After the war, the land was returned to its original owner, George Washington Custis Lee, the grandson of George Washington. In 1871, the government purchased the land from Lee's family, and the cemetery continued to grow.

In the 20th century, Arlington County experienced rapid suburbanization and urban development. The construction of the Pentagon in the 1940s and the expansion of federal agencies led to an influx of residents and increased economic activity. Today, Arlington County is known for its vibrant communities, bustling urban centers, and close proximity to Washington, D.C. It is also home to numerous landmarks, including the Pentagon, Arlington National Cemetery, and the Marine Corps War Memorial.