quickly led to settlement of the fertile Mohawk and Gennessee valleys and the Niagara Frontier . Buffalo and Rochester became boomtowns . Significant migration of New England "Yankees" (mainly of English descent) to the central and western parts of the state led to minor conflicts with the more settled "Yorkers" (mainly of German, Dutch, and Scottish descent). More than 15% of the state's 1850 population had been born in New England. The western part of the state grew fastest at this time. By 1840, New York was home to seven of the nation's thirty largest cities. [ Note 4 ] Hundreds of thousands of New York's young men fought during the Civil War , more than any other Northern state . A war was not in the best interest of business, because much of New York's trade was based on moving Southern goods. The city's large Democrat community feared the impact of Abraham Lincoln 's election in 1860 . By the time of the 1861 Battle of Fort Sumter , political differences had vanished and the state quickly met Lincoln's request for soldiers and supplies. While no battles were waged in New York, the state wasn't immune to Confederate conspiracies, including one to burn various New York cities and another to invade the state via Canada. [ 29 ] In 1863, Lincoln issued the Emancipation Proclamation , which freed the slaves in states that were still in rebellion against the union. In March 1863, the federal draft law was changed