Key Facts
- Duration
- 62 years (1808–1870)
- Enforcing body
- Royal Navy West Africa Squadron
- US involvement ended
- 1861 (start of American Civil War)
- Key treaty
- Webster–Ashburton Treaty, 1842
- US slavery abolished
- 1865, via 13th Amendment
Strategic Narrative Overview
The blockade evolved over decades as Britain secured bilateral agreements with more nations. The United States, whose 1807 Act Prohibiting Importation of Slaves was weakly enforced, joined through the Webster–Ashburton Treaty of 1842, committing both countries to cooperative anti-slave-trade patrols. American naval participation, largely focused on the Americas and mid-Atlantic, continued until the Civil War in 1861, after which the Lincoln administration granted Britain full authority to intercept US-flagged vessels.
01 / The Origins
Britain's 1807 Slave Trade Act made it illegal for British ships to transport enslaved people, taking effect in 1808. To enforce this prohibition, the Royal Navy deployed the West Africa Squadron off the African coast. Britain subsequently negotiated treaties with other nations granting the Royal Navy the right to intercept and search foreign vessels suspected of carrying slaves, extending the reach of abolition enforcement beyond British ships alone.
03 / The Outcome
US slavery was formally abolished by the 13th Amendment in 1865. The Royal Navy's West Africa Squadron continued operations until 1870, when the blockade was formally concluded. The campaign is credited with intercepting a significant portion of slave-trade voyages during the period, though enforcement varied considerably, and the transatlantic slave trade persisted in reduced form until near the end of the blockade.
Belligerents & Mobilization Analysis
Side A
2 belligerents
Side B
1 belligerent