Washington County is the first locality in the United States known to have been named for George Washington. It was formed from Fincastle County in 1776, and a part of Montgomery County was added in 1777.

Created by an act of 1776, court first met on 18 January 1777. Minute books for the periods 1787-1819 and 1821-1837 and many loose papers were lost in a courthouse fire set by Union soldier James Wyatt on 15 December 1864 during the Civil War. Wyatt, who was raised in Washington County, sought revenge for what he claimed was a wrong done against him by a county court judge before the war.

A fiduciary is a confidential and legal relationship which binds one person to act on behalf of another. A fiduciary is also a person who acts as a trustee for another.

Administrators' Bonds and Guardians' Bonds are of bonds that administrators and guardians were required to take out with the justices of the court to guarantee proper execution of their positions. The obligation was made binding by a money guarantee. The bonds show the names of the administrator or guardians and their sureties, the date, amount and condition of the obligation, name of the deceased, and signatures.

An Administrator is a person appointed by the court to manage the assets and liabilities of a person who dies without having written a valid will. An administrator may also be appointed if the testator leaves an incomplete will naming no executor, or if the named executor cannot or will not serve.

A Guardian is a person legally invested to take care of another person, and of the property and rights of that person. The guardians usually were responsible for the estate of underage children who were either orphans or had received a large inheritance.