Virginia's General Assembly has adopted a resolution, expressing "profound regret" for the role the US state played in slavery.
The resolution was passed by a 96-0 vote in the House and also unanimously backed in the 40-member Senate.
Although non-binding, the resolution sent an important symbolic message, its sponsors said.
Lawmakers also expressed regret for "the exploitation of Native Americans" in Virginia.
Saturday's resolution was passed as the state was preparing to mark the 400th anniversary of Jamestown, where the first Africans arrived in 1619.
It said that government-sanctioned slavery "ranks as the most horrendous of all depredations of human rights and violations of our founding ideals in our nation's history".
"The abolition of slavery was followed by systematic discrimination, enforced segregation, and other insidious institutions and practices toward Americans of African descent that were rooted in racism, racial bias, and racial misunderstanding," the resolution said.
The passage of the Thirteenth Amendment in 1865 officially ended slavery in the US.
In 2003, President George W Bush described the transatlantic slave trade as "one of the greatest crimes of history", without giving an outright apology.