This grant was sold to one land speculation company, while a second group of Indians from the same tribe claimed to another company that the Chief had been deposed, and that they were empowered to issue a grant, which they did to the second company. Following the Revolutionary War, both companies surveyed the territories and issued their own land grants to settlers, which frequently overlapped. It was not until after the War of 1812, when both companies were in financial straits, that they merged and reconciled all land claims.
The establishment of Indian Stream as an independent nation was essentially the result of the ambiguous boundary between the United States and Canada as defined in the Treaty of Paris, because there were three possible options for "the northwesternmost head of Connecticut River." As a result, the area (in and around the three tributaries that fed into the head of the Connecticut River) was not necessarily under the jurisdiction of either the U.S. or Canada.
The relevant text from the Treaty reads:
The Republic covered the northern reaches of what is now the state of New Hampshire, including the four Connecticut Lakes. Where the British claimed the southeasternmost branch (the chain of Connecticut Lakes), the U.S. claimed the border as we know it today (i.e., Hall's Stream, to the west—arguably a "northwesternmost headwater" of the Connecticut). Both sides sent in tax collectors and debt-collecting sheriffs. The double taxation in particular caused ire among the population, and the republic was formed to put an end to the issue until the U.S. and Britain could settle on the borderline.
The republic ceased to operate independently in 1835, when the New Hampshire Militia occupied the area, following a vote by the Indian Stream Congress to be annexed by the U.S. The vote arose from fears regarding a prior incident in which a group of "Streamers" invaded Canada to free a fellow citizen who had been arrested by a British sheriff and judge over a matter of an unpaid hardware store debt, as debtors' prison laws were still in force at the time. The invading posse shot up the judge's home where their comrade was being held, causing something of an international incident. The British Ambassador to the U.S. was astonished at the idea of a war with the States over a matter of a hardware-store debt and quickly agreed to engage in negotiations to resolve the long-simmering border disputes resulting from the poor wording of the Treaty of Paris.
Britain relinquished its claim in January 1836, and U.S. jurisdiction was acknowledged around May 1836. The area was still described as Indian Stream at the time of the 1840 U.S. Census taken June 1, 1840; the local population totalled 315. The area was incorporated as Pittsburg in 1840. Pittsburg has 300,000 acres (1,200 km²), or 282.3 square miles (731 km²) of land area and 9.0 square miles (23 km²) of inland water area.
In 1842, the land dispute was definitively resolved by the Webster-Ashburton Treaty and the land was assigned to New Hampshire. However, the 1845 Lewis Robinson Map of New Hampshire "Based on the latest authorities," has a northern boundary at the town of Clarksville, just south of modern-day Pittsburg.