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What 4 states were the border states?

The border states during the American Civil War were the four slave states of Delaware, Maryland, Kentucky, and Missouri. These states were called “border states” because they bordered states that had seceded from the Union. The border states were critical territory during the Civil War and both the Union and Confederacy badly wanted to control them.

Why Were They Called Border States?

The border states were the four slave states of Delaware, Maryland, Kentucky, and Missouri located between the free Northern states and the seceded Southern states. They were called “border states” because they literally bordered the dividing line between the Union and Confederacy.

When the Southern states began seceding from the Union starting in late 1860 after Abraham Lincoln’s election, it was unclear what these slave states caught in the middle would do. The border states had economies tied to slavery like the South, but were also deeply integrated into the Union politically and economically.

Both the Union and the Confederacy badly wanted the border states to join their side. Whoever controlled them would gain important economic resources, manpower for armies, and strategic territory adjoining their heartlands. This put the border states in a powerful position during the early part of the war.

The Strategic Importance of the Border States

There were several reasons why the border states were so strategically important during the Civil War:

  • The border states contained key rivers, railroads, and roads connecting the North to the South like the Potomac River, the Ohio River, and the Baltimore & Ohio Railroad.
  • The border states, though they had smaller populations than states farther north or south, provided vital manpower for military service.
  • Maryland, Kentucky, and Missouri had key cities like Baltimore, Louisville, and St. Louis which were important economic, transportation, and manufacturing hubs.
  • The border states provided agricultural production like tobacco, wheat, corn, and livestock to help supply troops.
  • The border states formed a strategic buffer zone limiting direct contact between the core Northern and Southern states.

For these reasons, both sides worked aggressively to keep the border states aligned with them. Losing the border states would have been a huge strategic setback that could have changed the outcome of the war.

The Positions of the Border States

Here was the stance of each border state as the Civil War began:


Delaware was the least committed to slavery of the border states with fewer than 2,000 slaveholders in a state of over 110,000 people. Delaware voted not to secede from the Union and supported the North during the war. Delaware’s small size and location made it easy for the Union to control.


Maryland was deeply divided over secession. Its economy was tied to slavery, but it also depended on trade and collaboration with the North. Maryland’s state legislature voted against seceding, spurring a failed pro-South coup attempt in 1861. After that, Union troops occupied Maryland and it remained in the Union.


Kentucky aimed to be neutral at first. It officially declared neutrality, but both sides violated this. A shadow Confederate government formed in Kentucky, while Union military camps were established in the state. Ultimately Kentucky stayed with the Union after Confederate troops invaded the state in 1862.


Like Maryland, Missouri was deeply divided. Its state convention voted against secession. When the pro-South governor tried to align with the Confederacy, it sparked fighting between pro-Union and pro-Confederate militias. Missouri remained in the Union but endured guerrilla warfare throughout the war.

The Roles of the Border States During the War

Here are some key roles the border states played after siding with the Union:

  • Over 100,000 men from the border states joined the Union Army, providing needed manpower.
  • The border states were a vital source of horses, mules, food, and supplies for Union troops.
  • Cities like Baltimore, Louisville, and St. Louis became centers for Union troop movements, hospitals, and training camps.
  • Union river gunboats were built in border state shipyards for river operations around Vicksburg and elsewhere.
  • The border states were a constant security concern, with Confederate raiders and guerrillas trying to undermine Union control.

At the same time, the Union had to tread carefully in the border states on the slavery issue. Abolitionist policies had to be incremental to avoid alienating their populations and politicians. Over the course of the war, the border states became more economically integrated with the North.

Gradual Emancipation in the Border States

The border states resisted blanket emancipation policies, but gradually took steps toward emancipation over the course of the war:

  • The District of Columbia passed compensated emancipation in April 1862 freeing 3,100 slaves.
  • In Maryland, a new state constitution passed in 1864 with emancipation provisions.
  • West Virginia, formed from western Virginia counties, had gradual emancipation written into its new constitution.
  • Missouri abolished slavery in January 1865. About 10,000 slaves gained freedom.
  • In Kentucky, the 13th Amendment abolished the last 1,000 slaves there by December 1865.

By fighting to preserve the Union rather than directly fighting against slavery, the border states ultimately aligned with the North. This gradual alignment allowed emancipation to take root in the border states by the end of the war.


The four border states of Delaware, Maryland, Kentucky, and Missouri played pivotal roles during the American Civil War. Their location bordering Union and Confederate states gave them great strategic importance. After Virginia’s secession, both sides vied intensely for the border states’ allegiance. Though divided internally on the issue, the border states ultimately stayed in the Union. They provided key manpower, supplies, and infrastructure support for the Union war effort. On the slavery issue, the border states took gradual steps toward emancipation during the course of the war. This helped cement their alignment with the North and Union by the end of the conflict.