Reasons for the Aroostook War for kids: 1783 Treaty of Paris
Following the Revolutionary War of Independence, the 1783 Treaty of Paris was signed ending hostilities between the United States and Great Britain and in which U.S. boundaries were established. In the Treaty of Paris the northeastern border of the United States was described as follows:

"From the northwest angle of Nova Scotia, to wit, that angle which is formed by a line drawn due north from the source of the St. Croix river to the highlands, along the said highlands which divide those rivers that empty themselves into the St. Lawrence, and those which fall into the Atlantic ocean, to the northwestern most head of the Connecticut river."

The description of the borders was very unclear. The reason for this was because the vast interior of the region had neither been explored nor mapped.

Reasons for the Aroostook War for kids: Background History
The basis of land claims in the Aroostook War dispute was based on the 1783 Treaty of Paris. Other treaties had been made clarifying borders such as the 1794 Jay Treaty nor the 1814 Treaty of Ghent. The Treaty of 1818 set the 49th parallel as the border with Canada from Rupert's Land west to the Rocky Mountains but the area of Aroostook was left undefined.  

Reasons for Aroostook War: Background History
The Treaty of Ghent restored things to the way they were before the War of 1812.  Article V addressed the unresolved border dispute - the demarcation of the "highlands" that were to be the boundary between the US and Britain's colonies. In order to achieve the peace terms the issue of the boundary was differed. Article V of the Treaty of Ghent stated:

• Commissioners were to be appointed, to survey the area and establish the border

• In the event that the commissioners disagreed, The British and the Americans agreed to put the decision in the hands of "some friendly sovereign or State"

• This impartial third party would determine the border between Maine, New Hampshire, Vermont and New York in the US, and New Brunswick and Lower Canada (Quebec)

Reasons for Aroostook War: Maine becomes a state
Maine became a state in 1820 and began granting land to settlers in the Aroostook Valley, ignoring British claims. The situation became more antagonistic. The "highlands" boundary separated rivers draining into the St. Lawrence from those entering the Atlantic. Maine insisted this height of land was north of the St. John River, whilst New Brunswick insisted the Penobscot watershed was the boundary line. The increased American settlement in the 1820s brought further tensions to the area, and these were made even worse when lumberjacks from Maine and New Brunswick converged on the timber adjacent to the Aroostook, Allagash, and St. John rivers.

Aroostook War: Arbitration by King William I of the Netherlands
The Commissioners attempting to agree the borders could not come to an agreement and put the decision in the hands of "some friendly sovereign or State". In 1831 King William I of the Netherlands was called upon to make an arbitrary decision on the disputed boundary.

Aroostook War: The Canadian Rebellions and the Caroline Affair
The Rebellions of 1837 were two armed uprisings that took place in Lower and Upper Canada in 1837 and 1838 leading to the Caroline affair that strained relations between the United States and British Canada even further.

Aroostook War: US Rejects the Arbitration Decision
The British accepted his decision but Maine were extremely unhappy, pressured the government and the US Senate rejected the arbitration decision. This sparked the International Incident known as the Aroostook War.

Aroostook War: Neutrality Law of 1838
The Neutrality Law of 1838 was passed empowering civil authorities to prevent border excursions.

Facts about Aroostook War
The following fact sheet contains interesting facts and information on Aroostook War.

During the winter of 1838/39 Canadian lumberjacks arrived in the disputed Aroostook area to cut timber - as did lumberjacks from Maine

The Maine legislature authorized Maine's land agent, Rufus McIntire, the Penobscot County sheriff, and a posse of volunteer militia to arrest the New Brunswick lumberjacks

Some New Brunswick lumberjacks were arrested and their equipment and animals confiscated

The Canadian lumberjacks raised their own posse and retaliated by seizing the land agent, Rufus McIntire, and others who had been sent to expel them

In March 1839 British troops from Quebec reached Madawaska, the American sector of Aroostook

Maine pressurized Congress authorized a force of 50,000 men and appropriated $10 million to address the crisis

Both Maine and New Brunswick called out their militia.

Maine actually sent 10,000 troops to Aroostook

President Van Buren sent General Winfield Scott to Aroostook to diffuse the situation

In March 1839 General Winfield Scott negotiated with an agreement the British negotiator, Sir John Harvey, agreeing a truce and a joint occupancy of the area in dispute until a satisfactory settlement could be reached

The officials of Maine and New Brunswick and the British agreed to refer the dispute to a boundary commission

The agreement averted all military action.

Neither side wanted an expensive war that would interrupt trade

No serious fighting actually took place during the Aroostook "War" although there were a couple of skirmishes and clashes between the lumberjacks

The boundary was later settled by the Webster-Ashburton Treaty of 1842